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Made available in DSpace on 2022-05-01T09:47:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Universidade Federal do Paraná Fundação Araucária Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Accidents involving Brown spiders are reported throughout the world. In the venom, the major toxins involved in the deleterious effects are phospholipases D (PLDs). In this work, recombinant mutated phospholipases D from three endemic species medically relevant in South America (Loxosceles intermedia, L. laeta and L. gaucho) were tested as antigens in a vaccination protocol. In such isoforms, key amino acid residues involved in catalysis, magnesium-ion coordination, and binding to substrates were replaced by Alanine (H12A-H47A, E32A-D34A and W230A). These mutations eliminated the phospholipase activity and reduced the generation of skin necrosis and edema to residual levels. Molecular modeling of mutated isoforms indicated that the three-dimensional structures, topologies, and surface charges did not undergo significant changes. Mutated isoforms were recognized by sera against the crude venoms. Vaccination protocols in rabbits using mutated isoforms generated a serum that recognized the native PLDs of crude venoms and neutralized dermonecrosis and edema induced by L. intermedia venom. Vaccination of mice prevented the lethal effects of L. intermedia crude venom. Furthermore, vaccination of rabbits prevented the cutaneous lesion triggered by the three venoms. These results indicate a great potential for mutated recombinant PLDs to be employed as antigens in developing protective vaccines for Loxoscelism. Department of Cell Biology Federal University of Paraná (UFPR) Production and Research Center of Immunobiological Products (CPPI) State Department of Health Veterinary Hospital Federal University of Paraná (UFPR) Department of Structural Molecular Biology and Genetics State University of Ponta Grossa (UEPG) Multiuser Center for Biomolecular Innovation Departament of Physics Universidade Estadual Paulista (UNESP) Multiuser Center for Biomolecular Innovation Departament of Physics Universidade Estadual Paulista (UNESP) Universidade Federal do Paraná: 02/2020 Universidade Federal do Paraná: 04/2019 Fundação Araucária: 057/2017 CNPq: 303868/2016-3 CNPq: 408633/2018-2

Chagas disease is an illness caused by the protozoan Trypanosoma cruzi that is distributed in 21 countries of Latin America. The main way of transmission of T. cruzi is through the feces of triatomines infected with the parasite. With technological advances came new technologies called omics. In the pre-genomic era, the omics science was based on cytogenomic studies of triatomines. With the Rhodnius prolixus genome sequencing project, new omics tools were applied to understand the organism at a systemic level and not just from a genomic point of view. Thus, the present review aims to put together the cytogenomic and genomic information available in the literature for Chagas disease vectors. Here, we review all studies related to cytogenomics and genomics of Chagas disease vectors, contributing to the direction of further research with these insect vectors, because it was evident that most studies focus on cytogenomic knowledge of the species. Given the importance of genomic studies, which contributed to the knowledge of taxonomy, systematics, as well as the vector’s biology, the need to apply these techniques in other genera and species of Triatominae subfamily is emphasized.

Summary Caseous lymphadenitis (CLA) is a small ruminant disease characterized by the development of granulomatous lesions in superficial and internal lymph nodes, as well as in some organs, and causes significant economic losses worldwide. The aetiological agent of CLA is the bacterium Corynebacterium pseudotuberculosis; however, the commercially available diagnostic tools present problems with regard to specificity, which can lead to false‐negative results. This study aimed to develop an indirect enzyme‐linked immunosorbent assay (ELISA) for the detection of specific immunoglobulins in goats and sheep using recombinant C. pseudotuberculosis PLD, CP40, PknG, DtxR and Grx proteins. For validation of the ELISAs, 130 goat serum samples and 160 sheep serum samples were used. The best ELISA for goats was developed using a combination of PLD and CP40 as antigens at a 1:1 ratio, which presented 96.9% sensitivity and 98.4% specificity. The most effective ELISA for sheep presented 91% sensitivity and 98.7% specificity when recombinant PLD alone was used as the antigen. These ELISAs can be used as highly accurate tools in epidemiological surveys and for the serodiagnosis of C. pseudotuberculosis infection in goats and sheep.

Made available in DSpace on 2021-06-25T10:55:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-03-01 National Institute of Biological Resources The potential outcome of flavivirus and alphavirus co-infections is worrisome due to the development of severe diseases. Hundreds of millions of people worldwide live under the risk of infections caused by viruses like chikungunya virus (CHIKV, genus Alphavirus), dengue virus (DENV, genus Flavivirus), and zika virus (ZIKV, genus Flavivirus). So far, neither any drug exists against the infection by a single virus, nor against co-infection. The results described in our study demonstrate the inhibitory potential of two flavonoids derived from citrus plants: Hesperetin (HST) against NS2B/NS3pro of ZIKV and nsP2pro of CHIKV and, Hesperidin (HSD) against nsP2pro of CHIKV. The flavonoids are noncompetitive inhibitors and the determined IC50 values are in low µM range for HST against ZIKV NS2B/NS3pro (12.6 ± 1.3 µM) and against CHIKV nsP2pro (2.5 ± 0.4 µM). The IC50 for HSD against CHIKV nsP2pro was 7.1 ± 1.1 µM. The calculated ligand efficiencies for HST were > 0.3, which reflect its potential to be used as a lead compound. Docking and molecular dynamics simulations display the effect of HST and HSD on the protease 3D models of CHIKV and ZIKV. Conformational changes after ligand binding and their effect on the substrate-binding pocket of the proteases were investigated. Additionally, MTT assays demonstrated a very low cytotoxicity of both the molecules. Based on our results, we assume that HST comprise a chemical structure that serves as a starting point molecule to develop a potent inhibitor to combat CHIKV and ZIKV co-infections by inhibiting the virus proteases. Multiuser Center for Biomolecular Innovation Departament of Physics Instituto de Biociências Letras e Ciências Exatas (Ibilce) Universidade Estadual Paulista (UNESP) Institute of Biological Information Processing (IBI-7: Structural Biochemistry) Forschungszentrum Jülich Federal University of Tocantins Instituto de Biociências Letras e Ciências Exatas (Ibilce) Universidade Estadual Paulista (UNESP) FACERES Medical School Faculdade de Medicina de São José do Rio Preto-FAMERP Institute of Physics Federal University of Mato Grosso do Sul Institut für Physikalische Biologie Heinrich-Heine-Universität Düsseldorf JuStruct: Jülich Centre for Structural Biology Forchungszentrum Jülich Multiuser Center for Biomolecular Innovation Departament of Physics Instituto de Biociências Letras e Ciências Exatas (Ibilce) Universidade Estadual Paulista (UNESP) Instituto de Biociências Letras e Ciências Exatas (Ibilce) Universidade Estadual Paulista (UNESP)

Made available in DSpace on 2021-06-25T11:14:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Phospholipases-D (PLDs) found in Loxosceles spiders’ venoms are responsible for the der-monecrosis triggered by envenomation. PLDs can also induce other local and systemic effects, such as massive inflammatory response, edema, and hemolysis. Recombinant PLDs reproduce all of the deleterious effects induced by Loxosceles whole venoms. Herein, wild type and mutant PLDs of two species involved in accidents—L. gaucho and L. laeta—were recombinantly expressed and character-ized. The mutations are related to amino acid residues relevant for catalysis (H12-H47), magnesium ion coordination (E32-D34) and binding to phospholipid substrates (Y228 and Y228-Y229-W230). Circular dichroism and structural data demonstrated that the mutant isoforms did not undergo significant structural changes. Immunoassays showed that mutant PLDs exhibit conserved epitopes and kept their antigenic properties despite the mutations. Both in vitro (sphingomyelinase activity and hemolysis) and in vivo (capillary permeability, dermonecrotic activity, and histopathological analysis) assays showed that the PLDs with mutations H12-H47, E32-D34, and Y228-Y229-W230 displayed only residual activities. Results indicate that these mutant toxins are suitable for use as antigens to obtain neutralizing antisera with enhanced properties since they will be based on the most deleterious toxins in the venom and without causing severe harmful effects to the animals in which these sera are produced. Departamento de Biologia Celular Universidade Federal do Paraná Centro de Produção e Pesquisa de Imunobiológicos (CPPI) Departamento de Física Centro Multiusuário de Inovação Biomolecular Universidade Estadual Paulista (UNESP) Departamento de Biologia Estrutural Molecular e Genética Universidade Estadual de Ponta Grossa Departamento de Física Centro Multiusuário de Inovação Biomolecular Universidade Estadual Paulista (UNESP) FAPESP: 2015/13765-0 FAPESP: 2019/10475-2 FAPESP: 2915/18868-2 CNPq: 303868/2016-3 CNPq: 307338/2014-2 CNPq: 309940/2019-2 CNPq: 408633/2018-2

Made available in DSpace on 2022-04-28T19:44:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Background: Snake venoms are composed of pharmacologically active proteins that are evolutionarily diverse, stable and specific to targets. Hence, venoms have been explored as a source of bioactive molecules in treating numerous diseases. Recent evidences suggest that snake venom proteins may affect the formation of new blood vessels. Excessive angiogenesis has been implicated in several pathologies including tumours, diabetic retinopathy, arthritis, inter alia. In the present study, we have examined the effects of P-I metalloproteinases isolated from Bothrops moojeni (BmMP-1) and Bothrops atrox (BaMP-1) and L-amino acid oxidases (LAAO) isolated from B. moojeni (BmLAAO) and B. atrox (BaLAAO) on biochemical and functional aspects of angiogenesis. Methods: P-I metalloproteinases and LAAO were purified from venom by molecular size exclusion and ion-exchange chromatography and subsequently confirmed using mass spectrometry. The P-I metalloproteinases were characterized by azocaseinolytic, fibrinogenolytic and gelatinase activity and LAAO activity was assessed by enzyme activity on L-amino acids. Influence of these proteins on apoptosis and cell cycle in endothelial cells was analysed by flow cytometry. The angiogenic activity was determined by in vitro 3D spheroid assay, Matrigel tube forming assay, and in vivo agarose plug transformation in mice. Results: P-I metalloproteinases exhibited azocaseinolytic activity, cleaved α and partially β chain of fibrinogen, and displayed catalytic activity on gelatin. LAAO showed differential activity on L-amino acids. Flow cytometry analysis indicated that both P-I metalloproteinases and LAAO arrested the cells in G0/G1 phase and further induced both necrosis and apoptosis in endothelial cells. In vitro, P-I metalloproteinases and LAAO exhibited significant antiangiogenic properties in 3D spheroid and Matrigel models by reducing sprout outgrowth and tube formation. Using agarose plug transplants in mice harbouring P-I metalloproteinases and LAAO we demonstrated a marked disruption of vasculature at the periphery. Conclusion: Our research suggests that P-I metalloproteinases and LAAO exhibit anti-angiogenic properties in vitro and in vivo. Manipal School of Life Sciences Manipal Academy of Higher Education Juggat Pharma Jagadale Industries Multiuser Center for Biomolecular Innovation Department of Physics São Paulo State University (UNESP), SP Multiuser Center for Biomolecular Innovation Department of Physics São Paulo State University (UNESP), SP

Made available in DSpace on 2021-06-25T11:05:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-12-01 Caseous lymphadenitis (CL) is a chronic infectious disease that affects sheep and goats. Many serological tests have been developed to detect the disease; one of the most widely used is the enzyme-linked immunosorbent assay (ELISA), due to its advantages, which include acceptable cost-effectiveness, applicability, sensitivity and specificity. ELISA formulations using recombinant proteins can exhibit significant sensitivity and specificity when using a single purified antigen. DTxR, Trx, TrxR, LexA, SodC, SpaC, NanH, and PknG recombinant proteins can be considered target proteins for ELISA development due to its extracellular or on the cell surface location, which allows a better recognition by the immune system. Therefore, the objectives of this study were to evaluate the antigenic reactivity of Corynebacterium pseudotuberculosis recombinant proteins in goat and sheep serum. Of eight proteins evaluated, rSodC was selected for validation assays with small ruminant serum samples from the semiarid region of the state of Bahia, Brazil. Validation assays with goat serum samples showed that ELISA-rSodC presented sensitivity and specificity of 96% and 94%, respectively. Validation assays with sheep serum showed that ELISA-rSodC exhibited sensitivity and specificity of 95% and 98%, respectively. Analysis of 756 field serum samples showed that rSodC identified 95 positive samples (23%) in goats and 75 positive samples (21%) in sheep. The ELISA with recombinant SodC protein developed in this study discriminated positive and negative serum samples with high levels of sensitivity and specificity. This formulation is promising for epidemiological surveys and CL control programs. Trial registration AEC No 4958051018. 12/18/2018, retrospectively registered Immunology and Molecular Biology Laboratory (LABIMUNO) Federal University of Bahia (UFBA) College of Science and Entrepreneurship (FACEMP) Feira de Santana State University (UEFS) Multiuser Center for Biomolecular Innovation (IBILCE/UNESP) Multiuser Center for Biomolecular Innovation (IBILCE/UNESP)

Since the first report of a new pneumonia disease in December 2019 (Wuhan, China) up to now WHO reported more than 50 million confirmed cases and more than one million losses, globally. The causative agent of COVID-19 (SARS-CoV-2) has spread worldwide resulting in a pandemic of unprecedented magnitude. To date, no clinically safe drug or vaccine is available and the development of molecules to combat SARS-CoV-2 infections is imminent. A well-known strategy to identify molecules with inhibitory potential against SARS-CoV-2 proteins is the repurposing of clinically developed drugs, e.g., anti-parasitic drugs. The results described in this study demonstrate the inhibitory potential of quinacrine and suramin against SARS-CoV-2 main protease (3CLpro). Quinacrine and suramin molecules present a competitive and non-competitive mode of inhibition, respectively, with IC50 and KD values in low μM range. Using docking and molecular dynamics simulations we identified a possible binding mode and the amino acids involved in these interactions. Our results suggested that suramin in combination with quinacrine showed promising synergistic efficacy to inhibit SARS-CoV-2 3CLpro. The identification of effective, synergistic drug combinations could lead to the design of better treatments for the COVID-19 disease. Drug repositioning offers hope to the SARS-CoV-2 control.

Made available in DSpace on 2020-12-10T19:47:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Renal cell carcinoma (RCC) consists of the most lethal common urological cancer and the clinical practice has shown that resistant RCC to commons therapies is extremely high. Berberine is an isoquinoline alkaloid, presents in different kinds of plants and it has long been used in Chinese medicine. It has several properties, such as antioxidant, anti-inflammatory, anti-diabetic, anti-microbial and anti-cancer. Moreover, berberine has photosensitive characteristics and its association with photodynamic therapy (PDT) is effective against tumor cells. This study aimed to evaluate the effects of berberine associated with PDT in renal carcinoma cell lines. The cellular viability assay showed increased cytotoxicity in concentration and time-dependent manner. Berberine presented efficient internalization in all cell lines analyzed. In addition, after treatment with berberine associated with PDT, it was observed a high phototoxicity effect with less than 20 % of viable cells. In this study we observed that the increase of reactive oxygen species (ROS) levels was accompanied by an increase of autophagy levels and apoptosis by caspase 3 activity, suggesting cell death by both mechanisms. Additionally, three target genes of anti-cancer drugs were differentially expressed in 786-O cells, being that Vascular Endothelial Growth Factor-D (FIGF) and Human Telomerase Reverse Transcriptase (TERT) gene presented low expression and Polo Like Kinase 3 (PLK3) presented overexpression after treatment with berberine associated with PDT. In this study, the proposed treatment triggered metabolites changes related to cell proliferation, tumorigenesis and angiogenesis. Thus, it was possible to suggest that berberine has promising potential as a photosensitizing agent in a photodynamic therapy, because it induced significant anticancer effects on renal carcinoma cells. Sao Paulo State Univ, Lab Genom Studies, Sao Jose Do Rio Preto, SP, Brazil Sao Paulo State Univ, Phys Dept, Sao Jose Do Rio Preto, SP, Brazil Sao Paulo State Univ, Multiuser Ctr Biomol Innovat, Sao Jose Do Rio Preto, SP, Brazil Univ Sao Paulo, Fac Philosophy Sci & Letters Ribeirao Preto, Ctr Nanotechnol & Tissue Engn Photobiol & Photome, Dept Chem, Ribeirao Preto, SP, Brazil Sao Paulo State Univ, Lab Genom Studies, Sao Jose Do Rio Preto, SP, Brazil Sao Paulo State Univ, Phys Dept, Sao Jose Do Rio Preto, SP, Brazil Sao Paulo State Univ, Multiuser Ctr Biomol Innovat, Sao Jose Do Rio Preto, SP, Brazil FAPESP: 2009/53989-4 CAPES: 88882.434430/2019-01

Phospholipase-B-like (SVPLB-like) enzymes are present in relatively small amounts in a number of venoms, however, their biological function and mechanisms of action are un-clear. A three-dimensional model of the SVPLB-like enzyme from Crotalus adamanteus was generated by homology modeling based on the crystal structures of bovine Ntn-hydrolyases and the modeled protein possesses conserved domains characteristic of Ntn-hydrolases. Molecular dynamics simulations indicate that activation by autocatalytic cleavage results in the removal of 25 amino acids which increases accessibility to the active site. SVPLB-like enzymes possess a highly reactive cysteine and are hence amidases that to belong to the N-terminal nucleophile (Ntn) hydrolase family. The Ntn-hydrolases (N-terminal nucleophile) form a superfamily of diverse enzymes that are activated autocatalytically; wherein the N-terminal catalytic nucleophile is implicated in the cleavage of the amide bond.

Arboviruses are transmitted by arthropods (arthropod-borne virus) which can be mosquitoes or other hematophagous arthropods, in which their life cycle occurs before transmission to other hosts. Arboviruses such as Dengue, Zika, Saint Louis Encephalitis, West Nile, Yellow Fever, Japanese Encephalitis, Rocio and Murray Valley Encephalitis viruses are some of the arboviruses transmitted biologically among vertebrate hosts by blood-taking vectors, mainly Aedes and Culex sp., and are associated with neurological, viscerotropic, and hemorrhagic reemerging diseases, posing as significant health and socioeconomic concern, as they become more and more adaptive to new environments, to arthropods vectors and human hosts. One of the main families that include mosquito-borne viruses is Flaviviridae, and here, we review the case of the Flavivirus genus, which comprises the viruses cited above, using a variety of research approaches published in literature, including genomics, transcriptomics, proteomics, metabolomics, etc., to better understand their structures as well as virus-host interactions, which are essential for development of future antiviral therapies.

Made available in DSpace on 2018-12-11T17:15:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-02-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Glutaredoxin A1 from Corynebacterium pseudotuberculosis was shown to be a mycoredoxin protein. In this study, we established a process to overexpress and purify glutaredoxin A1. The aim of this study was the investigation of the Glutaredoxin A1 from C. pseudotuberculosis behavior under different redox environments and the identification of lead molecules, which can be used for specific inhibitor development for this protein family. A quantitative assay was performed measuring the rate of insulin reduction spectrophotometrically at 640 nm through turbidity formation from the precipitation of the free insulin. Glutaredoxin A1, at 5 μM concentration, accelerated the reduction process of 0.2 mM insulin and 1 mM DTT. The pH optimum of the reaction was 7.4. In the presence of DTT and ESH the glutaredoxin A1 presents similar activity, and its activity is reduced by 50% in the presence of GSH. Additional function for ESH in the redox metabolism of C. pseudotuberculosis is suggested. A combined STD and Chemical Shift – NMR approach was employed to study the effects of potential inhibitors on the structure of glutaredoxin A1 from Corynebacterium pseudotuberculosis. The inhibitory potential of four ligands (heparin, suramin, hesperetin – Hst, and hesperidin - Hsp) against glutaredoxin A1 is discussed. Multiuser Center for Biomolecular Innovation Departament of Physics Instituto de Biociências Letras e Ciências Exatas (Ibilce) Universidade Estadual Paulista (UNESP) Institute of Chemistry University of Campinas (UNICAMP) Multiuser Center for Biomolecular Innovation Departament of Physics Instituto de Biociências Letras e Ciências Exatas (Ibilce) Universidade Estadual Paulista (UNESP) FAPESP: 2009/53989-4 FAPESP: 2015/13765-0 FAPESP: 2015/18868-2 FAPESP: 2016/08104-8; 2016/12904-0 CNPq: 307338/2014-2 CNPq: 401270/2014-9 CNPq: 435913/2016-6

Sphingomyelinases D have only been identified in arachnid venoms, Corynebacteria, Arcanobacterium, Photobacterium and in the fungi Aspergillus and Coccidioides. The arachnid and bacterial enzymes share very low sequence identity and do not contain the HKD sequence motif characteristic of the phospholipase D superfamily, however, molecular modeling and circular dichroism of SMases D from Loxosceles intermedia and Corynebacterium pseudotuberculosis indicate similar folds. The phospholipase, hemolytic and necrotic activities and mice vessel permeabilities were compared and both enzymes possess the ability to hydrolyze phospholipids and also promote similar pathological reactions in the host suggesting the existence of a common underlying mechanism in tissue disruption. J. Cell. Biochem. 118:2053-2063, 2017. © 2016 Wiley Periodicals, Inc.

The conformational stability of the Cold shock protein A (CspA) from C. pseudotuberculosis (Cp), a nucleic acid binding protein in function of pH and salt concentration was examined by using differential scanning calorimetry and CD spectroscopy in combination with computational analysis to identify the specify amino acids undergoing change. Our approach identified a sodiumbinding site in CpCspA and at pH 8.0 a significant reduction in the β-sheet content was observed which resulted in a decrease of the protein thermal stability. The computational analyses identified His30 and His65 as the amino acids with the largest charge shifts at different pHs. His30/His65 are part of the extensive hydrogen bonding network and along with the ion-binding site are essential for the conformational stability of CspA.

Spiders of the genus Loxosceles, popularly known as Brown spiders, are considered a serious public health issue, especially in regions of hot or temperate climates, such as parts of North and South America. Although the venoms of these arachnids are complex in molecular composition, often containing proteins with distinct biochemical characteristics, the literature has primarily described a family of toxins, the Phospholipases-D (PLDs), which are highly conserved in all Loxosceles species. PLDs trigger most of the major clinical symptoms of loxoscelism i.e., dermonecrosis, thrombocytopenia, hemolysis, and acute renal failure. The key role played by PLDs in the symptomatology of loxoscelism was first described 40 years ago, when researches purified a hemolytic toxin that cleaved sphingomyelin and generated choline, and was referred to as a Sphingomyelinase-D, which was subsequently changed to Phospholipase-D when it was demonstrated that the enzyme also cleaved other cellular phospholipids. In this review, we present the information gleaned over the last 40 years about PLDs from Loxosceles venoms especially with regard to the production and characterization of recombinant isoforms. The history of obtaining these toxins is discussed, as well as their molecular organization and mechanisms of interaction with their substrates. We will address cellular biology aspects of these toxins and how they can be used in the development of drugs to address inflammatory processes and loxoscelism. Present and future aspects of loxoscelism diagnosis will be discussed, as well as their biotechnological applications and actions expected for the future in this field.

Brown spider envenomation results in dermonecrosis with gravitational spreading characterized by a marked inflammatory reaction and with lower prevalence of systemic manifestations such as renal failure and hematological disturbances. Several toxins make up the venom of these species, and they are mainly peptides and proteins ranging from 5–40 kDa. The venoms have three major families of toxins: phospholipases-D, astacin-like metalloproteases, and the inhibitor cystine knot (ICK) peptides. Serine proteases, serpins, hyaluronidases, venom allergens, and a translationally controlled tumor protein (TCTP) are also present. Toxins hold essential biological properties that enable interactions with a range of distinct molecular targets. Therefore, the application of toxins as research tools and clinical products motivates repurposing their uses of interest. This review aims to discuss possibilities for brown spider venom toxins as putative models for designing molecules likely for therapeutics based on the status quo of brown spider venoms. Herein, we explore new possibilities for the venom components in the context of their biochemical and biological features, likewise their cellular targets, three-dimensional structures, and mechanisms of action.

Made available in DSpace on 2019-10-06T16:29:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-04-23 Vitamin B12 acts as a cofactor for various metabolic reactions important in living organisms. The Vitamin B12 biosynthesis is restricted to prokaryotes, which means, all eukaryotic organisms must acquire this molecule through diet. This study presents the investigation of Vitamin B12 metabolism and the characterization of precorrin-4 C(11)-methyltransferase (CobM), an enzyme involved in the biosynthesis of Vitamin B12 in Corynebacterium pseudotuberculosis. The analysis of the C. pseudotuberculosis genome identified two Vitamin B12-dependent pathways, which can be strongly affected by a disrupted vitamin metabolism. Molecular dynamics, circular dichroism, and NMR-STD experiments identified regions in CobM that undergo conformational changes after s-adenosyl-L-methionine binding to promote the interaction of precorrin-4, a Vitamin B12 precursor. The binding of s-adenosyl-L-methionine was examined along with the competitive binding of adenine, dATP, and suramin. Based on fluorescence spectroscopy experiments the dissociation constant for the four ligands and the target protein could be determined; SAM (1.4 ± 0.7 µM), adenine (17.8 ± 1.5 µM), dATP (15.8 ± 2.0 µM), and Suramin (6.3 ± 1.1 µM). The results provide rich information for future investigations of potential drug targets within the C. pseudotuberculosis's Vitamin B12 metabolism and related pathways to reduce the pathogen's virulence in its hosts. Multiuser Center for Biomolecular Innovation Departament of Physics Instituto de Biociências Letras e Ciências Exatas (Ibilce) Universidade Estadual Paulista (UNESP), São Jose do Rio Preto-SP Institute of Physics Federal University of Mato Grosso do Sul Multiuser Center for Biomolecular Innovation Departament of Physics Instituto de Biociências Letras e Ciências Exatas (Ibilce) Universidade Estadual Paulista (UNESP), São Jose do Rio Preto-SP

Made available in DSpace on 2019-10-06T16:09:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-03-15 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Currently no effective treatment is available to combat infections caused by Corynebacterium pseudotuberculosis in livestock. Survival of this Gram-positive bacterium in rapidly-growing pathogens in hostile environments is strongly dependent on the existence of a robust DNA repair system to prevent DNA mutations and contribute to bacterial colonization and virulence. The adenine/guanine-specific DNA glycosylase (MutY) is evolutionarily conserved and has been well characterized due to its central role in the prevention of mutagenesis and DNA repair. The aim of this study was the characterization of the target protein interaction with free adenine, suramin, and heparin, as well as the binding competition characterization between the molecules. The dissociation constant for free adenine interaction with Corynebacterium pseudotuberculosis MutY (Cp-MutY) was determined, 86 ± 2.5 μM. NMR competition experiments demonstrated, that the polyanions heparin and suramin compete with adenine for the protein active site. The determined dissociation constant for the heparin/Cp-MutY interaction was 5.9 ± 1.0 μM and for suramin was 16 ± 1.5 μM. Docking of both polyanions with Cp-MutY revealed a possible mode of interaction and indicates that these molecules can interfere with the protein interaction with damaged DNA or prevent the binding of the adenine base in the enzyme active site. Multiuser Center for Biomolecular Innovation Department of Physics Instituto de Biociências Letras e Ciências Exatas (Ibilce) Universidade Estadual Paulista (UNESP) Departamento de Física e Biofísica Instituto de Biociências Universidade Estadual Paulista Júlio de Mesquita Filho -UNESP Laboratory of Molecular Biology Universidade Federal de São João Del-Rei (CCO), Av. Sebastião Gonçalves Coelho, 400 Laboratório de Genética Celular e Molecular Instituto de Ciências Biológicas Universidade Federal de Minas Gerais, Av, Antônio Carlos, 6627 - Pampulha, CP 486, CEP 31 Multiuser Center for Biomolecular Innovation Department of Physics Instituto de Biociências Letras e Ciências Exatas (Ibilce) Universidade Estadual Paulista (UNESP) Departamento de Física e Biofísica Instituto de Biociências Universidade Estadual Paulista Júlio de Mesquita Filho -UNESP FAPESP: 2009/53989-4 FAPESP: 2015/13765-0 FAPESP: 2015/18868-2 FAPESP: 2016/08104-8 FAPESP: 2016/12904-0 CNPq: 307338/2014-2 CNPq: 401270/2014-9 CNPq: 435913/2016-6

Made available in DSpace on 2018-12-11T16:44:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-12-15 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The discovery of rapid acting and powerful angiogenic proteins are of significant interest in the treatment of various human disorders associated with insufficient angiogenesis such as ischemia, menorrhagia and delayed wound healing. Snake venoms consist of a mixture of bioactive proteins and polypeptides and are rich sources of pharmacologically important molecules. Serine proteinases are one of the abundant proteins present in Bothrops snake venoms and possess multiple biological functions including the regulation of the blood coagulation cascade. In this study, serine proteinases from Bothrops atrox (B. atrox) and Bothrops brazili (B. brazili) that modulate angiogenesis were purified and characterized. Molecular size exclusion chromatography, affinity chromatography followed by ion exchange chromatography of the serine proteinases indicated molecular masses of around 32 kDa. Serine proteinases from both the species exhibited diverse catalytic activities such as the ability to induce amidolytic, fibrinogenolytic, gelatinolytic activities and also coagulated plasma with a minimal coagulation concentration of 2.4 μg/mL. Serine proteinases facilitated the sprouting of human umbilical vein endothelial cells (HUVEC) in three-dimensional culture systems and induced tubule formation in monolayer culture systems. Serine proteinase stimulated Aktser473 and eNOSser1177 phosphorylation in endothelial cells and addition of PI3K inhibitor LY294002 abrogated the effects of serine proteinases on sprout formation of endothelial cells in 3D collagen gels, suggesting that serine proteinase facilitated angiogenesis was mediated by PI3K/eNOS signaling axis. We also show in agarose plug assays using a mouse model, serine proteinases from Bothrops venoms significantly enhanced neovascularization. Our data suggests pro-angiogenic activity by the serine proteinases from B. atrox and B. brazili venom and further studies are warranted to explore the therapeutic applications. School of Life Sciences Manipal University Multiuser Center for Biomolecular Innovation IBILCE/UNESP Juggat Pharma Jagadale Industries Multiuser Center for Biomolecular Innovation IBILCE/UNESP FAPESP: 2015/13765-0 FAPESP: 401388/2013-1 FAPESP: MCTI/CNPq/DBT

Loxoscelism refers to the clinical symptoms that develop after brown spider bites. Brown spider venoms contain several phospholipase-D isoforms, which are the main toxins responsible for both the cutaneous and systemic effects of loxoscelism. Understanding of the phospholipase-D catalytic mechanism is crucial for the development of specific treatment that could reverse the toxic effects caused by the spider bite. Based on enzymatic, biological, structural, and thermodynamic tests, we show some features suitable for designing drugs against loxoscelism. Firstly, through molecular docking and molecular dynamics predictions, we found three different molecules (Suramin, Vu0155056, and Vu0359595) that were able to bind the enzyme's catalytic site and interact with catalytically important residues (His12 or His47) and with the Mg2+ co-factor. The binding promoted a decrease in the recombinant brown spider venom phospholipase-D (LiRecDT1) enzymatic activity. Furthermore, the presence of the inhibitors reduced the hemolytic, dermonecrotic, and inflammatory activities of the venom toxin in biological assays. Altogether, these results indicate the mode of action of three different LiRecDT1 inhibitors, which were able to prevent the venom toxic effects. This strengthen the idea of the importance of designing a specific drug to treat the serious clinical symptoms caused by the brown spider bite, a public health problem in several parts of the world, and until now without specific treatment. J. Cell. Biochem. 118: 726-738, 2017. © 2016 Wiley Periodicals, Inc.

Brown spider phospholipases D from Loxosceles venoms are among the most widely studied toxins since they induce dermonecrosis, triggering inflammatory responses, increase vascular permeability, cause hemolysis, and renal failure. The catalytic (H12 and H47) and metal-ion binding (E32 and D34) residues in Loxosceles intermedia phospholipase D (LiRecDT1) were mutated to understand their roles in the observed activities. All mutants were identified using whole venom serum antibodies and a specific antibody to wild-type LiRecDT1, they were also analyzed by circular dichroism (CD) and differential scanning calorimetry (DSC). The phospholipase D activities of H12A, H47A, H12A-H47A, E32, D34 and E32A-D34A, such as vascular permeability, dermonecrosis, and hemolytic effects were inhibited. The mutant Y228A was equally detrimental to biochemical and biological effects of phospholipase D, suggesting an essential role of this residue in substrate recognition and binding. On the other hand, the mutant C53A-C201A reduced the enzyme's ability to hydrolyze phospholipids and promote dermonecrosis, hemolytic, and vascular effects. These results provide the basis understanding the importance of specific residues in the observed activities and contribute to the design of synthetic and specific inhibitors for Brown spider venom phospholipases D.

Made available in DSpace on 2020-12-12T02:00:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-07-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The arginine repressor (ArgR) regulates the expression of genes involved in arginine biosynthesis. Upon attaining a threshold concentration of arginine in the cytoplasm, the trimeric C-terminal domain of ArgR binds three arginines in a shallow surface cleft and subsequently hexamerizes forming a dimer of trimers containing six Arg co-repressor molecules which are buried at the subunit interfaces. The N-terminal domains of this complex bind to the DNA promoter thereby interrupting the transcription of the genes related to Arg biosynthesis. The crystal structures of the wild type and mutant Pro115Gln ArgR from Corynebacterium pseudotuberculosis determined at 1.7 Å demonstrate that a single amino acid substitution switches co-repressor specificity from Tyr to Arg. Molecular dynamics simulations indicate that the first step, i.e., the binding of the co-repressor, occurs in the trimeric state and that Pro115Gln ArgR preferentially binds Arg. It was also shown that, in Pro115 ArgR hexamers, the concomitant binding of sodium ions shifts selectivity to Tyr. Structural data combined with phylogenetic analyses of ArgR from C. pseudotuberculosis suggest that substitutions in the binding pocket at position 115 may alter its specificity for amino acids and that the length of the protein interdomain linker can provide further functional flexibility. These results support the existence of alternative ArgR regulatory mechanisms in this pathogenic bacterium. Multiuser Center for Biomolecular Innovation IBILCE/UNESP Department of Physics IBILCE/UNESP Brazilian Synchrotron Light Laboratory (LNLS) Brazilian Center for Research in Energy and Materials (CNPEM) Laboratory of Molecular Evolution IBILCE/UNESP Multiuser Center for Biomolecular Innovation IBILCE/UNESP Department of Physics IBILCE/UNESP Laboratory of Molecular Evolution IBILCE/UNESP FAPESP: 2015/13765-0 FAPESP: 2015/18868-2 FAPESP: 2016/19995-0 FAPESP: 2016/24587-9 FAPESP: 2018/07977-3 FAPESP: 2018/10736-8

Plant viruses invade and spread through their hosts either via the short-distance movement which involves the spreading of the virus from the infected cell to the adjacent cell.

Zika virus (ZIKV) has been associated with serious health conditions, and an intense search to discover different ways to prevent and treat ZIKV infection is underway. Berberine and emodin possess several pharmacological properties and have been shown to be particularly effective against the entry and replication of several viruses. We show that emodin and berberine trigger a virucidal effect on ZIKV. When the virus was exposed to 160 &micro, M of berberine, a reduction of 77.6% in the infectivity was observed, when emodin was used (40 &micro, M), this reduction was approximately 83.3%. Dynamic light scattering data showed that both compounds significantly reduce the hydrodynamic radius of virus particle in solution. We report here that berberine and emodin, two natural compounds, have strong virucidal effect in Zika virus.

Exfoliative toxins (ETs) are secreted virulence factors produced by staphylococci. These serine proteases specifically cleave desmoglein 1 (Dsg1) in mammals and are key elements in staphylococcal skin infections. We recently identified a new et gene in S. aureus O46, a strain isolated from ovine mastitis. In the present study, we characterized the new et gene at a genetic level and the enzymatic activity of the deduced protein. The S. aureus O46 genome was re-assembled, annotated and compared with other publicly available S. aureus genomes. The deduced amino acid sequence of the new et gene shared 40%, 53% and 59% sequence identity to those of ETA, ETB and ETD, respectively. The new et gene shared the same genetic vicinity and was similar in other S. aureus strains bearing this gene. The recombinant enzyme of the new et gene caused skin exfoliation in vivo in neonatal mice. The new et-gene was thus named ete, encoding a new type (type E) of exfoliative toxin. We showed that ETE degraded the extracellular segments of Dsg1 in murine, ovine and caprine epidermis, as well as in ovine teat canal epithelia, but not that in bovine epidermis. We further showed that it directly hydrolyzed human and swine Dsg1 as well as murine Dsg1α and Dsg1β, but not canine Dsg1 or murine Dsg1γ. Molecular modeling revealed a correlation between the preferred orientation of ETE docking on its Dsg1 cleavage site and species-specific cleavage activity, suggesting that the docking step preceding cleavage accounts for the ETE species-specificity. This new virulence factor may contribute to the bacterial colonization on the stratified epithelia in certain ruminants with mastitis.

Made available in DSpace on 2019-10-06T16:21:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-06-15 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Financiadora de Estudos e Projetos Myceliophthora heterothallica is a thermophilic fungus potentially relevant for the production of enzymes involved in the degradation of plant biomass. A xylanase encoding gene of this species was identified by means of RT-PCR using primers designed based on a xylanase coding sequence (GH11) of the fungus M. thermophila. The obtained gene was ligated to the vector pET28a(+) and the construct was transformed into Escherichia coli cells. The recombinant xylanase (r-ec-XylMh) was heterologously expressed, and the highest activity was observed at 55 °C and pH 6. The enzyme stability was greater than 70% between pH 4.5 and 9.5 and the inclusion of glycerol (50%) resulted in a significant increase in thermostability. Under these conditions, the enzyme retained more than 50% residual activity when incubated at 65 °C for 1 h, and approximately 30% activity when incubated at 70 °C for the same period. The tested cations did not increase xylanolytic activity, and the enzyme indicated significant tolerance to several phenolic compounds after 24 h, as well as high specificity for xylan, with no activity for other substrates such as CMC (carboxymethylcellulose), Avicel, pNPX (p-nitrophenyl-β-D-xylopyranoside) and pNPA (p-nitrophenyl-α-L-arabinofuranoside), and is thus, of potential relevance in pulp bleaching. Graduate Program in Microbiology (UNESP) School of Agricultural and Veterinary Studies (FCAV-UNESP) Biosciences Institute (IB-UNESP) Multiuser Center for Biomolecular Innovation Department of Physics UNESP Department of Biology Biosciences Languages and Exact Sciences Institute (IBILCE-UNESP) Department of Chemistry and Environmental Sciences Biosciences Languages and Exact Sciences Institute (IBILCE-UNESP) Graduate Program in Microbiology (UNESP) School of Agricultural and Veterinary Studies (FCAV-UNESP) Biosciences Institute (IB-UNESP) Multiuser Center for Biomolecular Innovation Department of Physics UNESP Department of Biology Biosciences Languages and Exact Sciences Institute (IBILCE-UNESP) Department of Chemistry and Environmental Sciences Biosciences Languages and Exact Sciences Institute (IBILCE-UNESP)

Vitamin B

Made available in DSpace on 2018-12-11T16:59:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-02-01 Southern bean mosaic virus (SBMV) RNA purified from infected plants was used for cloning the viral genome-linked protein (VPg) and was subsequently expressed in Escherichia coli. Circular dichroism (CD), dynamic light scattering (DLS) and saturation transfer difference (STD) by nuclear magnetic resonance (NMR) measurements were employed to determine the degree of monodispersity and to investigate the conformational changes in the absence and presence of trifluoroethanol (TFE) which indicated increased helical content with increasing concentration of TFE. 8-Anilino-1-naphthalenesulfonic acid (ANS) was used as a probe to compare the unfolding regions of the protein before and after addition of TFE. The results indicated that although the TFE concentration influences VPg folding, it does not play a role in nucleotide binding and that the local solvent hydrophobicity causes significant conformational changes. Multiuser Center for Biomolecular Innovation IBILCE/UNESP Department of Physics IBILCE/UNESP Laboratory for Structural Biology of Infection and Inflammation Hamburg University Multiuser Center for Biomolecular Innovation IBILCE/UNESP Department of Physics IBILCE/UNESP

The eastern brown snake is the predominant cause of snakebites in mainland Australia. Its venom induces defibrination coagulopathy, renal failure and microangiopathic hemolytic anemia. Cardiovascular collapse has been described as an early cause of death in patients, but, so far, the mechanisms involved have not been fully identified. In the present work, we analysed the venome of Pseudonaja textilis by combining high throughput proteomics and transcriptomics, aiming to further characterize the components of this venom. The combination of these techniques in the analysis and identification of toxins, venom proteins and putative toxins allowed the sequence description and the identification of the following: prothrombinase coagulation factors, neurotoxic textilotoxin phospholipase A2 (PLA2) subunits and “acidic PLA2”, three-finger toxins (3FTx) and the Kunitz-type protease inhibitor textilinin, venom metalloproteinase, C-type lectins, cysteine rich secretory proteins, calreticulin, dipeptidase 2, as well as evidences of Heloderma lizard peptides. Deep data-mining analysis revealed the secretion of a new transcript variant of venom coagulation factor 5a and the existence of a splicing variant of PLA2 modifying the UTR and signal peptide from a same mature protein. The transcriptome revealed the diversity of transcripts and mutations, and also indicates that splicing variants can be an important source of toxin variation.

2S albumins, the seed storage proteins, are the primary sources of carbon and nitrogen and are involved in plant defense. The mature form of Moringa oleifera (M. oleifera), a chitin binding protein isoform 3-1 (mMo-CBP3-1) a thermostable antifungal, antibacterial, flocculating 2S albumin is widely used for the treatment of water and is potentially interesting for the development of both antifungal drugs and transgenic crops. The crystal structure of mMo-CBP3-1 determined at 1.7 Å resolution demonstrated that it is comprised of two proteolytically processed α-helical chains, stabilized by four disulfide bridges that is stable, resistant to pH changes and has a melting temperature (TM) of approximately 98 °C. The surface arginines and the polyglutamine motif are the key structural factors for the observed flocculating, antibacterial and antifungal activities. This represents the first crystal structure of a 2S albumin and the model of the pro-protein indicates the structural changes that occur upon formation of mMo-CBP3-1 and determines the structural motif and charge distribution patterns for the diverse observed activities.

The gram-positive bacterium Corynebacterium pseudotuberculosis is the causative agent of different diseases that cause dramatically reduced yields of wool and milk, and results in weight loss, carcass condemnation and also death mainly in sheep, equids, cattle and goats and therefore globally results in considerable economical loss. Cold shock proteins are conserved in many bacteria and eukaryotic cells and they help to restore normal cell functions after cold shock in which some appear to have specific functions at normal growth temperature as well. Cold shock protein A from C. pseudotuberculosis was expressed in Escherichia coli and purified. The thermal unfolding/refolding process characterized by circular dichroism, differential scanning calorimetry and NMR spectroscopy techniques indicated that the refolding process was almost completely reversible.

Made available in DSpace on 2018-12-11T17:20:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-10-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul In pathogens, the thioredoxin system forms part of the defense against oxidative stress and ensures the formation of the proper disulfide bonds to ensure protein function. In Corynebacterium pseudotuberculosis, the role and mechanism of TrxA1 has not been elucidated, but, the significant homology among different Trxs and the conservation of the residues that form their active sites underline the importance of the Trx systems. Proteins involved in redox metabolism and low molecular weight thiols, which might interact with them, become attractive targets to modulate the activity of pathogens. The activity of the protein was investigated using a turbidimetric assay system. The influence of different pH and low molecular weight thiols were tested. Additionally, this assay was used to investigate the inhibitory potential of ligands from different molecular families, such as, polyanions (suramin and heparin) and flavonoids (hesperetin and hesperidin). All four compounds showed inhibition of the protein activity by approximately 80%. The interactions between these compounds and Cp-TrxA1 were investigated using CD spectroscopy, NMR, molecular docking and dynamics. Our results demonstrate that suramin and hesperetin can serve as lead molecules for the development of specific inhibitors for the C. pseudotuberculosis TrxA1. Multiuser Center for Biomolecular Innovation Department of Physics Instituto de Biociências Letras e Ciências Exatas (Ibilce) Universidade Estadual Paulista (UNESP) Institute of Physics Federal University of Mato Grosso do Sul Chemical Biology Laboratory Organic Chemistry Department Institute of Chemistry University of Campinas (UNICAMP) Multiuser Center for Biomolecular Innovation Department of Physics Instituto de Biociências Letras e Ciências Exatas (Ibilce) Universidade Estadual Paulista (UNESP) CNPq: 150444/2017-6 FAPESP: 2009/53989-4 FAPESP: 2015/13765-0 FAPESP: 2015/18868-2 FAPESP: 2016/08104-8 FAPESP: 2016/12904-0 Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul: 23/200.307/2014 CNPq: 307338/2014-2 CNPq: 401270/2014-9 CNPq: 435913/2016-6

The gram-positive bacteria Corynebacterium pseudotuberculosis, the causative agent of caseous lymphadenitis in livestock significantly reduces productivity and often causes death. The adenine/guanine-specific DNA glycosylase (MutY) prevents mutations in the DNA of the pathogen and a unique feature of the MutY protein family is the [4Fe–4S]2+ cluster that interlinks two protein subdomains. MutY from C. pseudotuberculosis was expressed in E. coli and purified, the CD experiments indicate a high content of α-helices and random coiled secondary structure and a typical near-UV CD fingerprint for the [4Fe–4S]2+ cluster. EDTA and copper sulfate possess a strong destabilizing effect on the [4Fe–4S]2+ cluster. UV–vis and fluorescence spectroscopy results demonstrate that between pH3.0 and 4.0 the integrity of the [4Fe–4S]2+ cluster is destroyed. To investigate the thermal stability of the protein differential scanning calorimetry and fluorescence spectroscopy were used and the Tm was determined to be 45°C. The analysis presented provides information concerning the protein stability under different physio-chemical conditions.

Cold shock proteins (Csps) function to preserve cell viability at low temperatures by binding to nucleic acids and consequently control gene expression. The mesophilic bacterium Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis in animals, and infection in livestock is a considerable economic burden worldwide. In this report, the structure of cold shock protein A from Cp (Cp-CspA) and biochemical analysis of its temperature-dependent interaction with a Y-box ssDNA motif is presented. The Cp-CspA structure contains five β-strands making up a β-barrel fold with 11 hydrophobic core residues and two salt bridges that confers it with a melting temperature of ~ 54 °C that is similar to mesophilic Bs-CspB. Chemical shift perturbations analysis revealed that residues in the nucleic acid-binding motifs (RNP 1 and 2) and loop 3 are involved in binding to the Y-box fragment either by direct interaction or by conformational rearrangements remote from the binding region. Fluorescence quenching experiments of Cp-CspA showed that the dissociation constants for Y-box ssDNA binding is nanomolar and the binding affinity decreased as the temperature increased, indicating that the interaction is enthalpically driven and the hydrogen bonds and van der Waals forces are important contributions for complex stabilization. The Y31 of Cp-CspA is a particular occurrence among Csps from mesophilic bacteria that provide a possible explanation for the higher binding affinity to ssDNA than that observed for Bs-CspB. Anisotropy measurements indicated that the reduction in molecular mobility of Cp-CspA upon Y-box binding is characterized by a cooperative process. DATABASE Resonance assignment and structural data are available in the Biological Magnetic Resonance Data Bank and Protein Data Bank under accession number 26802 and 5O6F, respectively.

The Pseudechis colletti and Pseudechis butleri venoms were analyzed by 1-D gel electrophoresis, followed by mass spectrometric analysis of tryptic peptides obtained from the protein bands. Both venoms contain highly potent pharmacologically active components, which were assigned to the following protein families: basic and acidic phospholipases A2 (PLA2s), L-amino acid oxidases (LAAOs), P-III metalloproteinases (P-III SVMPs), 5'- nucleotidases (5'-NTDs), cysteine-rich secretory proteins (CRISPs), venom nerve growth factors (VNGFs) and post-synaptic neurotoxins. Considerable predominance of PLA2s over other toxins is a characteristic feature of both venoms. The major differences in the venom compositions are the higher concentration of SVMPs and CRISPs in the P. butleri venom, as well as the presence of post-synaptic neurotoxins. Furthermore, the analysis revealed a high concentration of proteins with myotoxic, coagulopathic and apoptotic activities. PLA2s are responsible for the myotoxic and anticoagulant effects observed in patients after envenomation (4). The other protein families, encountered in the two venoms, probably contribute to the major symptoms described for these venoms. These results explain the observed clinical effects of the black snake envenomation. The analyzed venoms contain group P-III metalloproteinases of medical importance with the potency to be used for diagnostic purposes of von Willebrand factor (vWF) disease, for regulation of vWF in thrombosis and haemostasis, for studying the function of the complement system in host defense and in the pathogenesis of diseases. Comparison of venomic data showed similarities in the major venom components of snakes from the genus Pseudechis, resulting in common clinical effects of envenomation, and demonstrating close relationships between venom toxins of Elapidae snakes.

The Australian Elapidae spotted black snake Pseudechis guttatus venom proteome composition was analyzed by high throughput mass spectrometry. The crude venom proteins were decomplexed by 2D-PAGE and in-gel digestion peptides from 66 spot samples and analyzed by tandem mass spectrometry–LC-ESI-ion trap. Protein identification was performed combining PEAKS studio 7.0 and Mascot software. The analysis identified l -amino-acid oxidases, phospholipases A2, metalloproteases, nerve growth factors and ecto-5′-nucleotidases, and for the first time in this venom the components cysteine-rich secretory proteins similar to pseudechetoxin, phospholipase B and transferrin-like protein. The envenomation symptoms are in agreement with the identified components, but the present limitations of database information might impair the detection of toxin families, protein species and still unknown toxins. From the qualitative point of view, the similarity of this venom with the ones from other Pseudechis species could be assigned to recent speciation events. Biological significance Studies on the proteome of Australian Elapidae (Ancanthophiinae) are quite rare. In the present work we performed, using classic proteomic methods, a qualitative and partial analysis of the proteic components of Pseudechis guttatus venom. Although previous studies contributed to the knowledge of the major components of this venom, our study revealed some yet undescribed protein species, as well as new toxins, such as CRiSPs, phospholipase B, transferrin-like protein and ecto 5′-nucleotidase.

Snake venom metalloproteinases (SVMPs) belonging to P-I class are able to hydrolyze extracellular matrix proteins and coagulation factors triggering local and systemic reactions by multiple molecular mechanisms that are not fully understood. BmooMPα-I, a P-I class SMVP from Bothrops moojeni venom, was active upon neuro- and vaso-active peptides including angiotensin I, bradykinin, neurotensin, oxytocin and substance P. Interestingly, BmooMPα-I showed a strong bias towards hydrolysis after proline residues, which is unusual for most of characterized peptidases. Moreover, the enzyme showed kininogenase activity similar to that observed in plasma and cells by kallikrein. FRET peptide assays indicated a relative promiscuity at its S2–S′2 subsites, with proline determining the scissile bond. This unusual post-proline cleaving activity was confirmed by the efficient hydrolysis of the synthetic combinatorial library MCA-GXXPXXQ-EDDnp, described as resistant for canonical peptidases, only after Pro residues. Structural analysis of the tripeptide LPL complexed with BmooMPα-I, generated by molecular dynamics simulations, assisted in defining the subsites and provided the structural basis for subsite preferences such as the restriction of basic residues at the S2 subsite due to repulsive electrostatic effects and the steric impediment for large aliphatic or aromatic side chains at the S1 subsite. These new functional and structural findings provided a further understanding of the molecular mechanisms governing the physiological effects of this important class of enzymes in envenomation process.

Made available in DSpace on 2014-12-03T13:11:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-03-01Bitstream added on 2014-12-03T13:22:45Z : No. of bitstreams: 1 WOS000335755700005.pdf: 1237419 bytes, checksum: 63efa3a070a9fc1de02aeccb01a674cd (MD5) Deutsche Forschungsgemeinschaft Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Higher Education Commission of Pakistan German Academic Exchange Service (DAAD), Germany Alexander von Humboldt Foundation Elapid snake venom is a highly valuable, but till now mainly unexplored, source of pharmacologically important peptides. We analyzed the peptide fractions with molecular masses up to 10 kDa of two elapid snake venoms-that of the African cobra, N. m. mossambica (genus Naja), and the Peninsula tiger snake, N. scutatus, from Kangaroo Island (genus Notechis). A combination of chromatographic methods was used to isolate the peptides, which were characterized by combining complimentary mass spectrometric techniques. Comparative analysis of the peptide compositions of two venoms showed specificity at the genus level. Three-finger (3-F) cytotoxins, bradykinin-potentiating peptides (BPPs) and a bradykinin inhibitor were isolated from the Naja venom. 3-F neurotoxins, Kunitz/basic pancreatic trypsin inhibitor (BPTI)-type inhibitors and a natriuretic peptide were identified in the N. venom. The inhibiting activity of the peptides was confirmed in vitro with a selected array of proteases. Cytotoxin 1 (P01467) from the Naja venom might be involved in the disturbance of cellular processes by inhibiting the cell 20S-proteasome. A high degree of similarity between BPPs from elapid and viperid snake venoms was observed, suggesting that these molecules play a key role in snake venoms and also indicating that these peptides were recruited into the snake venom prior to the evolutionary divergence of the snakes. Univ Hamburg, Inst Biochem & Mol Biol, Lab Struct Biol Infect & Inflammat, DESY, D-22603 Hamburg, Germany Univ Engn & Technol, Dept Chem, Lahore 54890, Pakistan Univ Hamburg, Inst Organ Chem, D-20146 Hamburg, Germany Univ Med Ctr Hamburg Eppendorf UKE, Inst Clin Chem, D-20246 Hamburg, Germany IBILCE UNESP, Dept Phys, BR-15054000 Sao Jose Do Rio Preto, SP, Brazil Inst Pesquisas Energet & Nucl, Ctr Biotecnol, BR-05508000 Sao Paulo, Brazil IBILCE UNESP, Dept Phys, BR-15054000 Sao Jose Do Rio Preto, SP, Brazil Deutsche ForschungsgemeinschaftBE 1443-18-1 Deutsche Forschungsgemeinschaft26-1 Alexander von Humboldt Foundation3.3-BUL/1073481 STP

Envenomation by Bothrops species results, among other symptoms, in hemostatic disturbances. These changes can be ascribed to the presence of enzymes, primarily serine proteinases some of which are structurally similar to thrombin and specifically cleave fibrinogen releasing fibrinopeptides. A rapid, three-step, chromatographic procedure was developed to routinely purify serine proteinases from the venoms of Bothrops alternatus and Bothrops moojeni. The serine proteinase from B. alternatus displays an apparent molecular mass of similar to 32 kDa whereas the two closely related serine proteinases from B. moojeni display apparent molecular masses of similar to 32 kDa and similar to 35 kDa in SDS-PAGE gels. The partial sequences indicated that these enzymes share high identity with serine proteinases from the venoms of other Bothrops species. These proteins coagulate plasma and possess fibrinogenolytic activity but lack fibrinolytic activity. (C) 2013 Elsevier Ltd. All rights reserved.

The crystal structure of the myotoxic, cell-penetrating, basic polypeptide crotamine isolated from the venom ofCrotalus durissus terrificushas been determined by single-wavelength anomalous dispersion techniques and refined at 1.7 Å resolution. The structure reveals distinct cationic and hydrophobic surface regions that are located on opposite sides of the molecule. This surface-charge distribution indicates its possible mode of interaction with negatively charged phospholipids and other molecular targets to account for its diverse pharmacological activities. Although the sequence identity between crotamine and human β-defensins is low, the three-dimensional structures of these functionally related peptides are similar. Since crotamine is a leading member of a large family of myotoxic peptides, its structure will provide a basis for the design of novel cell-penetrating molecules.