7 results on '"Marcelo V. Liberato"'
Search Results
2. Chemical stability of a cold-active cellulase with high tolerance toward surfactants and chaotropic agent
- Author
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Thaís V. Souza, Juscemácia N. Araujo, Viviam M. da Silva, Marcelo V. Liberato, Agnes C. Pimentel, Thabata M. Alvarez, Fabio M. Squina, and Wanius Garcia
- Subjects
Cellulase ,Cold-active ,Cellulose ,Surfactant ,Detergent additives ,Biotechnology ,TP248.13-248.65 - Abstract
CelE1 is a cold-active endo-acting glucanase with high activity at a broad temperature range and under alkaline conditions. Here, we examined the effects of pH on the secondary and tertiary structures, net charge, and activity of CelE1. Although variation in pH showed a small effect in the enzyme structure, the activity was highly influenced at acidic conditions, while reached the optimum activity at pH 8. Furthermore, to estimate whether CelE1 could be used as detergent additives, CelE1 activity was evaluated in the presence of surfactants. Ionic and nonionic surfactants were not able to reduce CelE1 activity significantly. Therefore, CelE1 was found to be promising candidate for use as detergent additives. Finally, we reported a thermodynamic analysis based on the structural stability and the chemical unfolding/refolding process of CelE1. The results indicated that the chemical unfolding proceeds as a reversible two-state process. These data can be useful for biotechnological applications.
- Published
- 2016
- Full Text
- View/download PDF
3. Oxidative cleavage of polysaccharides by a termite-derived superoxide dismutase boosts the degradation of biomass by glycoside hydrolases
- Author
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João Paulo L. Franco Cairo, Fernanda Mandelli, Robson Tramontina, David Cannella, Alessandro Paradisi, Luisa Ciano, Marcel R. Ferreira, Marcelo V. Liberato, Lívia B. Brenelli, Thiago A. Gonçalves, Gisele N. Rodrigues, Thabata M. Alvarez, Luciana S. Mofatto, Marcelo F. Carazzolle, José G. C. Pradella, Adriana F. Paes Leme, Ana M. Costa-Leonardo, Mário Oliveira-Neto, André Damasio, Gideon J. Davies, Claus Felby, Paul H. Walton, and Fabio M. Squina
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OLIGOSACCHARIDES ,ENHANCEMENT ,DISCOVERY ,SUGARCANE BAGASSE ,CELLULOSE ,COPPER ,DECONSTRUCTION ,Environmental Chemistry ,PRETREATMENT ,Pollution ,LIGNOCELLULOSE ,LIGNIN - Abstract
Wood-feeding termites effectively degrade plant biomass through enzymatic degradation. Despite their high efficiencies, however, individual glycoside hydrolases isolated from termites and their symbionts exhibit anomalously low effectiveness in lignocellulose degradation, suggesting hereto unknown enzymatic activities in their digestome. Herein, we demonstrate that an ancient redox-active enzyme encoded by the lower termite Coptotermes gestroi, a Cu/Zn superoxide dismutase (CgSOD-1), plays a previously unknown role in plant biomass degradation. We show that CgSOD-1 transcripts and peptides are up-regulated in response to an increased level of lignocellulose recalcitrance and that CgSOD-1 localizes in the lumen of the fore- and midguts of C. gestroi together with termite main cellulase, CgEG-1-GH9. CgSOD-1 boosts the saccharification of polysaccharides by CgEG-1-GH9. We show that the boosting effect of CgSOD-1 involves an oxidative mechanism of action in which CgSOD-1 generates reactive oxygen species that subsequently cleave the polysaccharide. SOD-type enzymes constitute a new addition to the growing family of oxidases, ones which are up-regulated when exposed to recalcitrant polysaccharides, and that are used by Nature for biomass degradation.
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- 2022
4. Structural and functional insights of the catalytic GH5 and Calx-β domains from the metagenome-derived endoglucanase CelE2
- Author
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Agnes C. Pimentel, Marcelo V. Liberato, João Paulo L. Franco Cairo, Geizecler Tomazetto, César A. Gandin, Mario de Oliveira Neto, Thabata M. Alvarez, and Fabio M. Squina
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Bioengineering ,Applied Microbiology and Biotechnology ,Biochemistry ,Biotechnology - Published
- 2023
5. Oxidative cleavage of polysaccharides by a termite-derived
- Author
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João Paulo L, Franco Cairo, Fernanda, Mandelli, Robson, Tramontina, David, Cannella, Alessandro, Paradisi, Luisa, Ciano, Marcel R, Ferreira, Marcelo V, Liberato, Lívia B, Brenelli, Thiago A, Gonçalves, Gisele N, Rodrigues, Thabata M, Alvarez, Luciana S, Mofatto, Marcelo F, Carazzolle, José G C, Pradella, Adriana F, Paes Leme, Ana M, Costa-Leonardo, Mário, Oliveira-Neto, André, Damasio, Gideon J, Davies, Claus, Felby, Paul H, Walton, and Fabio M, Squina
- Abstract
Wood-feeding termites effectively degrade plant biomass through enzymatic degradation. Despite their high efficiencies, however, individual glycoside hydrolases isolated from termites and their symbionts exhibit anomalously low effectiveness in lignocellulose degradation, suggesting hereto unknown enzymatic activities in their digestome. Herein, we demonstrate that an ancient redox-active enzyme encoded by the lower termite
- Published
- 2021
6. The
- Author
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Robson, Tramontina, João Paulo L, Franco Cairo, Marcelo V, Liberato, Fernanda, Mandelli, Amanda, Sousa, Samantha, Santos, Sarita Cândida, Rabelo, Bruna, Campos, Jaciane, Ienczak, Roberto, Ruller, André R L, Damásio, and Fabio Marcio, Squina
- Subjects
Aldo–keto reductase ,Research ,Coptotermes gestroi ,Bioethanol ,Detoxification ,Reactive oxygen species - Abstract
Background In nature, termites can be considered as a model biological system for biofuel research based on their remarkable efficiency for lignocellulosic biomass conversion. Redox enzymes are of interest in second-generation ethanol production because they promote synergic enzymatic activity with classical hydrolases for lignocellulose saccharification and inactivate fermentation inhibitory compounds produced after lignocellulose pretreatment steps. Results In the present study, the biochemical and structural characteristics of the Coptotermes gestroi aldo–keto reductase (CgAKR-1) were comprehensively investigated. CgAKR-1 displayed major structural differences compared with others AKRs, including the differences in the amino acid composition of the substrate-binding site, providing basis for classification as a founding member of a new AKR subfamily (family AKR1 I). Immunolocalization assays with anti-CgAKR-1 antibodies resulted in strong fluorescence in the salivary gland, proventriculus, and foregut. CgAKR-1 supplementation caused a 32% reduction in phenolic aldehydes, such as furfural, which act as fermentation inhibitors of hemicellulosic hydrolysates, and improved ethanol fermentation by the xylose-fermenting yeast Scheffersomyces stipitis by 45%. We observed synergistic enzymatic interactions between CgAKR-1 and commercial cellulosic cocktail for sugarcane bagasse saccharification, with a maximum synergism degree of 2.17 for sugar release. Our data indicated that additive enzymatic activity could be mediated by reactive oxygen species because CgAKR-1 could produce hydrogen peroxide. Conclusion In summary, we identified the founding member of an AKRI subfamily with a potential role in the termite digestome. CgAKR-1 was found to be a multipurpose enzyme with potential biotechnological applications. The present work provided a basis for the development and application of integrative and multipurpose enzymes in the bioethanol production chain. Electronic supplementary material The online version of this article (doi:10.1186/s13068-016-0688-6) contains supplementary material, which is available to authorized users.
- Published
- 2016
7. X-ray structure and molecular dynamics simulations of endoglucanase 3 from Trichoderma harzianum: structural organization and substrate recognition by endoglucanases that lack cellulose binding module.
- Author
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Érica T Prates, Ivana Stankovic, Rodrigo L Silveira, Marcelo V Liberato, Flávio Henrique-Silva, Nei Pereira, Igor Polikarpov, and Munir S Skaf
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Medicine ,Science - Abstract
Plant biomass holds a promise for the production of second-generation ethanol via enzymatic hydrolysis, but its utilization as a biofuel resource is currently limited to a large extent by the cost and low efficiency of the cellulolytic enzymes. Considerable efforts have been dedicated to elucidate the mechanisms of the enzymatic process. It is well known that most cellulases possess a catalytic core domain and a carbohydrate binding module (CBM), without which the enzymatic activity can be drastically reduced. However, Cel12A members of the glycosyl hydrolases family 12 (GHF12) do not bear a CBM and yet are able to hydrolyze amorphous cellulose quite efficiently. Here, we use X-ray crystallography and molecular dynamics simulations to unravel the molecular basis underlying the catalytic capability of endoglucanase 3 from Trichoderma harzianum (ThEG3), a member of the GHF12 enzymes that lacks a CBM. A comparative analysis with the Cellulomonas fimi CBM identifies important residues mediating interactions of EG3s with amorphous regions of the cellulose. For instance, three aromatic residues constitute a harboring wall of hydrophobic contacts with the substrate in both ThEG3 and CfCBM structures. Moreover, residues at the entrance of the active site cleft of ThEG3 are identified, which might hydrogen bond to the substrate. We advocate that the ThEG3 residues Asn152 and Glu201 interact with the substrate similarly to the corresponding CfCBM residues Asn81 and Arg75. Altogether, these results show that CBM motifs are incorporated within the ThEG3 catalytic domain and suggest that the enzymatic efficiency is associated with the length and position of the substrate chain, being higher when the substrate interact with the aromatic residues at the entrance of the cleft and the catalytic triad. Our results provide guidelines for rational protein engineering aiming to improve interactions of GHF12 enzymes with cellulosic substrates.
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- 2013
- Full Text
- View/download PDF
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