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A histidine acid phosphatase (HAP) (PhySc) with 99.50% protein sequence similarity with PHO5 from Saccharomyces cerevisiae was expressed functionally with the molecular mass of ∼110 kDa through co-expression along with the set of molecular chaperones dnaK, dnaJ, GroESL. The purified HAP illustrated the optimum activity of 28.75 ± 0.39 U/mg at pH 5.5 and 40 ˚C. The Km and Kcat values towards calcium phytate were 0.608 ± 0.09 mM and 650.89 ± 3.6 s− 1. The half-lives (T1/2) at 55 and 60 ˚C were 2.75 min and 55 s, respectively. The circular dichroism (CD) demonstrated that PhySc includes 30.5, 28.1, 21.3, and 20.1% of random coils, α-Helix, β-Turns, and β-Sheet, respectively. The Tm recorded by CD for PhySc was 56.5 ± 0.34˚C. The molecular docking illustrated that His59 and Asp322 act as catalytic residues in the PhySc. MD simulation showed that PhySc at 40 ˚C has higher structural stability over those of the temperatures 60 and 80 ˚C that support the thermodynamic in vitro investigations. Secondary structure content results obtained from MD simulation indicated that PhySc consists of 34.03, 33.09, 17.5, 12.31, and 3.05% of coil, helix, turn, sheet, and helix310, respectively, which is almost consistent with the experimental results. [ABSTRACT FROM AUTHOR]

Post-translational modifications (PTMs) are protein modifications that occur after protein biosynthesis, playing a crucial role in regulating protein function. They are involved in the functional expression of G-protein-coupled receptors (GPCRs), as well as intracellular and secretory protein signaling. Here, we aimed to investigate the PTMs of the apelin receptor (APLNR), a GPCR and their potential influence on the receptor's function. In an in vitro experiment using HEK cells, we only observed glycosylation as a PTM of the APLNR and ineffective receptor signaling by the agonist, (Pyr1)-apelin-13. In contrast, when analyzing mouse spinal cord, we detected glycosylation and other PTMs, excluding isopeptidation. This suggests that additional PTMs are involved in the functional expression of the APLNR in vitro. In summary, these findings suggest that the APLNR in vivo requires multiple PTMs for functional expression. To comprehensively understand the pharmacological effects of the APLNR, it is essential to establish an in vitro system that adequately replicates the receptor's PTM profile. Nonetheless, it is crucial to overcome the challenge of heat-sensitive proteolysis in APLNR studies. By elucidating the regulation of PTMs, further research has the potential to advance the analysis and pharmacological studies of both the apelin/APLNR system and GPCR signal modulation.

Farnesyl/geranylgeranyl diphosphate synthases (FPPS/GGPPS) as the short‐chain prenyltransferases catalyse the formation of the acyclic precursors (E)‐FPP and (E)‐GGPP for isoprenoid biosynthesis. Here, we first cloned the cDNAs encoding FPPS and GGPPS in the vetch aphid Megoura viciae (designated as MvFPPS and MvGGPPS). They had an open reading frame of 1185 and 930 bp in length, encoding 395 and 309 amino acids, with a theoretical isoelectric point of 6.52 and 6.21, respectively. Sequence alignment and phylogenetic analysis showed that MvFPPS and MvGGPPS shared the conserved aspartate‐rich motifs characterized by all prenyltransferases identified to date and were clustered with their homologues in two large clades. RNA interference (RNAi) combined with gas chromatography/mass spectrometry (GC–MS) analysis showed that both MvFPPS and MvGGPPS were involved in the biosynthesis of alarm pheromone. Spatiotemporal expression profiling showed that the expression of MvFPPS and MvGGPPS was significantly higher in embryos than in other tissues. RNAi and GC–MS performed specifically in embryos corroborated the function of MvFPPS and MvGGPPS. In vitro, enzymatic activity assay and product analysis demonstrated that MvFPPS could catalysed the formation of (E)‐FPP using DMAPP or (E)‐GPP as the allylic cosubstrates in the presence of IPP, while MvGGPPS could only use (E)‐GPP or (E)‐FPP as cosubstrates. Functional interaction analysis using RNAi revealed that MvGGPPS exerts unidirectional functional compensation for MvFPPS. Moreover, it can regulate the biosynthesis of alarm pheromone by imposing a negative feedback regulation on MvFPPS. Our study helps to understand the molecular regulatory mechanism of terpenoid biosynthesis in the aphid. [ABSTRACT FROM AUTHOR]

Abstract Background This study aimed to analyze the in vitro effect of micro-strain stress on the proliferation and functional marker expression in chondrocytes isolated from human osteoarthritis cartilage samples. Methods Chondrocytes isolated from human osteoarthritis cartilage samples were subjected to loading with different types of micro-strain stress. The proliferation activity was assessed by flow cytometry, and the functional expression of chondrocyte markers was detected by qRT-PCR and western blot. Results Flow cytometry results showed stimulation of proliferation of human osteoarthritic chondrocytes when an adequate micro-strain stress was applied. qRT-PCR and western blot results showed that micro-strain stress promotes human osteoarthritic chondrocyte functional marker expression. These features coincide with the upregulation of multiple proteins and genes affecting cell proliferation and functional chondrocyte marker expression, including cyclin D1, collagen II, and Rock. Conclusion Adequate micro-strain stress could activate the Rho/Rock signaling pathway in osteoarthritic chondrocytes, thus transmitting mechanical signals to the cytoskeleton. This process leads to cytoskeleton reorganization, and transmission of the mechanical signals to the downstream effectors to promote proliferation and functional marker expression of osteoarthritic chondrocytes.

A new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant known as Omicron has caused a rapid increase in recent global patients with coronavirus infectious disease 2019 (COVID-19). To overcome the COVID-19 Omicron variant, production of a recombinant spike receptor binding domain (RBD) is vital for developing a subunit vaccine or a neutralizing antibody. Although bacterial expression has many advantages in the production of recombinant proteins, the spike RBD expressed in a bacterial system experiences a folding problem related to disulfide bond formation. In this study, the soluble Omicron RBD was obtained by a disulfide isomerase-assisted periplasmic expression system in Escherichia coli. The Omicron RBD purified from E. coli was very well recognized by anti-SARS-CoV-2 antibodies, sotrovimab (S309), and CR3022, which were previously reported to bind to various SARS-CoV-2 variants. In addition, the kinetic parameters of the purified Omicron RBD upon binding to the human angiotensin-converting enzyme 2 (ACE2) were similar to those of the Omicron RBD produced in the mammalian expression system. These results suggest that an E. coli expression system would be suitable to produce functional and correctly folded spike RBDs of the next emerging SARS-CoV-2 variants quickly and inexpensively. [ABSTRACT FROM AUTHOR]

The antitumor drug doxorubicin is widely used in clinical practice. However, the low yield and high cost of this drug highlight the urgent need for cost-effective processes to rapidly manufacture antitumor drugs at scale. In the biosynthesis pathway, the multi-functional cytochrome P450 enzyme DoxA catalyzes the last three steps of hydroxylation. The final conversion of daunorubicin to doxorubicin is the rate-limiting step. In our work, the DoxA has been expressed with the ferredoxin reductase FDR2 and the ferredoxin FDX1 and purified to homogeneous. The reduced carbon monoxide difference spectroscopy, heme concentration, and enzymatic characteristic were characterized. These studies suggest an approach for engineering Streptomyces P450s with functional expression for mechanistic and structural studies. [ABSTRACT FROM AUTHOR]

β-1,3-glucanase, a member of the plant PR-2 family of pathogenesis-related (PR) proteins and Glycoside Hydrolase Family 17 (GH17), plays an important role in plant defense mechanisms against pathogens. In this study, a β-1,3-glucanase gene from Picea asperata was isolated and designated as PaGlu; the gene consisted of a 1035 bp open reading frame (ORF) encoding 344 amino acid residues. Multiple alignment and phylogenetic analysis showed that PaGlu has the (91.86%) highest identity and the closest relationship with the β-1,3-glucanase of Picea sitchensis. qRT-PCR analysis revealed that the PaGlu gene was mainly expressed in the needles of Pheidole asperata. Furthermore, the expression of the PaGlu gene was significantly upregulated by L. piceae, suggesting that it is involved in the defense response of P. asperata against L. piceae infection. The optimal induction condition for recombinant PaGlu in Escherichia coli was incubation with 0.6 mM IPTG (isopropyl β-D-thiogalactoside) for 6 h at 25 °C, and the molecular weight of recombinant PaGlu was determined to be approximately 53 kDa. The purified recombinant PaGlu displayed high enzyme activity (20.7 U/mg) and the optimal conditions were pH 6.0 and 50 °C. In addition, the purified recombinant PaGlu exhibited a different destructive effect on the mycelium of Lophodermium piceae, Colletotrichum gloeosporioides, Fusarium proliferatum and Fusarium sporotrichioides. Importantly, it was able to destroy the hyphal wall of L. piceae. These results provide a molecular basis for further understanding of the mechanisms of the PaGlu gene in P. asperata against L. piceae infection. [ABSTRACT FROM AUTHOR]

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Background: This study aimed to analyze the in vitro effect of micro-strain stress on the proliferation and functional marker expression in chondrocytes isolated from human osteoarthritis cartilage samples. Methods: Chondrocytes isolated from human osteoarthritis cartilage samples were subjected to loading with different types of micro-strain stress. The proliferation activity was assessed by flow cytometry, and the functional expression of chondrocyte markers was detected by qRT-PCR and western blot. Results: Flow cytometry results showed stimulation of proliferation of human osteoarthritic chondrocytes when an adequate micro-strain stress was applied. qRT-PCR and western blot results showed that micro-strain stress promotes human osteoarthritic chondrocyte functional marker expression. These features coincide with the upregulation of multiple proteins and genes affecting cell proliferation and functional chondrocyte marker expression, including cyclin D1, collagen II, and Rock. Conclusion: Adequate micro-strain stress could activate the Rho/Rock signaling pathway in osteoarthritic chondrocytes, thus transmitting mechanical signals to the cytoskeleton. This process leads to cytoskeleton reorganization, and transmission of the mechanical signals to the downstream effectors to promote proliferation and functional marker expression of osteoarthritic chondrocytes. [ABSTRACT FROM AUTHOR]

Defensins, as part of the PR protein family, not only have antimicrobial activity in vitro, but also play an important role in plant disease resistance. To explore the molecular function of defensin in spruce, a defensin gene PaDef was isolated and characterized from Picea asperata. The full-length cDNA sequence of the PaDef was 264 bp and contained an ORF of 252 bp, encoding a total of 83 amino acids. The deduced PaDef protein belongs to the gamma-thionin family and contains the Knot1 domain and eight conserved cysteine residues. Blast and phylogenetic analysis showed that the PaDef protein shared high homology with other plant defensin proteins. The tertiary structure of PaDef was obtained by homologous modelling using the structure of Pinus sylvestris defensin as a template and exhibited a βαββ structure. SDS-PAGE analysis showed that the molecular mass of recombinant PaDef expressed in Escherichia coli was 23.8 kDa. Plate assay showed that purified PaDef exhibited strong antifungal activity inhibiting the growth of Pestalotiopsis neolitseae, but not Colletotrichum gloeosporioides and Botrytis cinerea. Microscopic observation revealed that purified PaDef had a negative effect on the hyphal morphology of all three phytopathogens. qRT-PCR analysis indicated that the PaDef gene had the highest expression level in needles of P. asperata compared with roots, phloem, twigs, and could be significantly upregulated by the pathogenic fungus Lophodermium piceae, which causes needle cast disease. These results provide a molecular basis for determining the molecular function of defensin PaDef in P. asperata and its potential as an antifungal agent. [ABSTRACT FROM AUTHOR]

This study focuses on an overlooked but critical issue: the composition and functional expression of microbial communities on the concrete surface in different areas of sewer pipes. Three immersion conditions were applied to simulate the duration of concrete in different areas ofsewers exposed to sewage, including short-term (L1), long-term (L2) and permanent immersion (L3). The properties of concrete under different immersion conditions and the bacterial diversity and functional capabilities in biofilms on the concrete surface were analyzed. Results showed that the L1 group was dominated by Halothiobacillus , whereas Desulfomicrobium was prominent in the L3 group. Significant differences in the predominant functional microbial communities and metabolic functional genes further confirmed the strong impact of immersion time on the pathways of microbial sulfur metabolism and concrete performance in sewer environment. Compared with the L2 and L3 groups, the decreased sewage immersion time resulted in an increase in the abundance and metabolic activity of sulfur-oxidizing bacteria in the L1 group. Hence, greater mass loss and gypsum production of concrete was found in the L1 group. The structural and functional differentiation of bacterial communities on the concrete surface observed in this study contributes to a better understanding of the uneven corrosion in real sewer pipes. [Display omitted] • Immersion conditions alter bacterial population involved in sulfur metabolism. • Sulfur oxidation functional genes are dominant under short-term immersion condition. • Biological sulfur oxidation can cause significant corrosion on concrete surfaces. [ABSTRACT FROM AUTHOR]

A high serum uric acid (SUA) concentration is associated with hyperuricemia (HUA) and gout. In order to obtain long-acting therapeutic effect, correction of purine metabolism at genetic level is advantageous. For this purpose, we expressed three "human-like" urate oxidases in human hepatocytes (HL-7702) by lentivirus-mediated transduction. Enzymatic assay revealed that the recombinant urate oxidases expressed in HL-7702 cells were functionally active. Electron microscopy study showed that the recombinant enzymes were localized to peroxisome and formed distinct crystalloid core structures as in other mammal cells. Although similar rate of uric acid degradation was observed for all recombinant urate oxidases, HL-7702-pLVX-UOX 83 cells and HL-7702-pLVX-UOX 214/217 cells retained more cell viability compared with HL-7702-pLVX-UOX PBC at high uric acid level. This study provides a new direction for the treatment of gout and hyperuricemia. [ABSTRACT FROM AUTHOR]

Summary: Black pepper (Piper nigrum L.) is known for its high content of piperine, a cinnamoyl amide derivative regarded as largely responsible for the pungent taste of this widely used spice. Despite its long history and worldwide use, the biosynthesis of piperine and related amides has been enigmatic up to now. In this report we describe a specific piperic acid CoA ligase from immature green fruits of P. nigrum. The corresponding enzyme was cloned and functionally expressed in E. coli. The recombinant enzyme displays a high specificity for piperic acid and does not accept the structurally related feruperic acid characterized by a similar C‐2 extension of the general C6–C3 phenylpropanoid structure. The enzyme is also inactive with the standard set of hydroxycinnamic acids tested including caffeic acid, 4‐coumaric acid, ferulic acid, and sinapic acid. Substrate specificity is corroborated by in silico modelling that suggests a perfect fit for the substrate piperic acid to the active site of the piperic acid CoA ligase. The CoA ligase gene shows its highest expression levels in immature green fruits, is also expressed in leaves and flowers, but not in roots. Virus‐induced gene silencing provided some preliminary indications that the production of piperoyl‐CoA is required for the biosynthesis of piperine in black pepper fruits. Significance Statement: In this report we provide biochemical and molecular evidence for a piperic acid CoA ligase from black pepper fruits, capable to produce piperoyl‐CoA from piperic acid, which both are considered precursors in the biosynthesis of piperine and related piperamides, the pungent principle of the Piperaceae. [ABSTRACT FROM AUTHOR]

Human fibroblast growth factor 7 (hFGF7) is a member of the paracrine-acting FGF family and mediates various reactions such as wound healing, tissue homeostasis, and liver regeneration. These activities make it a plausible candidate for pharmaceutical applications as a drug. However, the low expression level and stability of the recombinant hFGF7 were known to be major hurdles for further applications. Here, the expression level and stability of hFGF7 were attempted to improve by changing the order of amino acids through circular permutation (CP), thereby expecting an alternative fate according to the N-end rule. CP-hFGF7 variants were constructed systematically by using putative amino acid residues in the loop region that avoided the disruption of the structural integrity especially in the functional motif. Among them, cp-hFGF7 115-114 revealed a relatively higher expression level in the soluble fraction than the wild-type hFGF7 and was efficiently purified (7 mg L -1 ) to apparent homogeneity. The activity and stability of the purified variant cp-hFGF7 115-114 were comparable or superior to that of the wild-type hFGF7, thereby strongly suggesting that CP could be an alternative tool for the functional expression of hFGF7 in Escherichia coli., (© 2024 Wiley‐VCH GmbH.)

An integrated approach for real‐time oscillatory stability assessment (OSA) based on mutual information theory is proposed in this study. An advanced maximum‐relevance minimum‐redundancy (MRMR) ensemble scheme is designed to explore the internal relations between operation variables and the oscillatory stability margin (OSM). Multiple MRMR procedures are generated in parallel to select multiple different feature subsets, in which each feature presents a relevant and complementary description of OSM. The functional expression of the relationships is obtained by curve fitting. The 21‐bus system and 1648‐bus system are implemented to test the performance of the proposed approach. A compared investigation is made with some other data mining methods. The impacts of the number of feature sets, size of feature sets, size of training set, invalid data and computation time are studied. Experimental results reveal that the proposed approach provides faster and more accurate assessment results and is a real‐time adaptive approach for OSA. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the reliability of lactic acid bacteria (LAB) as heterologous hosts for the expression of MPB70 and MPB83, two Mycobacterium bovis antigens that possess diagnostics and immunogenic properties, respectively. We therefore generated recombinant cells of Lactococcus lactis and Lactobacillus plantarum that carried hybrid genes encoding MPB70 and MPB83 fused to signal peptides that are specifically recognized by LAB. Only L. lactis was able to secrete MPB70 using the L. lactis signal peptide Usp45, and to produce MPB83 as an immunogenic membrane protein following its expression with the signal peptide of the L. plantarum lipoprotein prsA. Inactivated cells of MPB83-expressing L. lactis cultures enhanced NF-κB activation in macrophages. Our results show that L. lactis is a reliable host for the secretion and functional expression of antigens that are naturally produced by M. bovis , the causative agent of bovine tuberculosis (bTB). This represents the first step on a long process to establishing whether recombinant LAB could serve as a food-grade platform for potential diagnostic tools and/or vaccine interventions for use against bTB, a chronic disease that primarily affects cattle but also humans and a wide range of domestic and wild animals. [ABSTRACT FROM AUTHOR]

Here, a complete set of recombinant fission yeast strains that coexpress each of the 57 human cytochrome P450 (CYP) enzymes together with their natural human electron transfer partner(s) was cloned. This strain collection was tested with two luminogenic probe substrates, and 31 human CYPs (including the orphan enzymes CYP2A7, CYP4A22 and CYP20A1) were found to metabolize at least one of these. Since other substrates are known for the remaining enzymes, all human CYPs are now shown to be active. Interestingly, CYP5A1 was found for the first time to work on a substrate other than prostaglandin H2, and, moreover, to catalyze an aliphatic hydroxylation reaction that consumes molecular oxygen. Also, the ability of CYP11A1 to catalyze an aryl hydroxylation is another unexpected result. [ABSTRACT FROM AUTHOR]

The aim of this study was to establish a system for the functional expression, purification and identification of new subtypes of modified antioxidant peptides from Pinctada fucata muscle (named MMP). After molecular modification, MMP had a primary coil spatial conformation that resembled an α-helix and improved the functional activity of MMP. The MMP DNA sequence was modified and codon optimized based on the amino acid sequence of the natural antioxidant peptide (named MP), which was isolated and purified from Pinctada fucata muscle by enzymatic hydrolysis. Antioxidant activity assay results showed that the IC50 values for DPPH-radical scavenging activity, superoxide-radical scavenging activity and hydroxyl-radical scavenging activity of MMP were 0.056, 0.310 and 0.126 mg/ml, respectively, which were higher than the antioxidant activities of enzymatically digested or chemically synthesized MMP (p < 0.05). In addition, this protocol exhibited great advantage in purity, speed, cost, and degree of automation for preparing MMP compared with enzymatic hydrolysis or chemical synthesis. Thus, the proposed method can be used to obtain MMP with high antioxidant activity and at a high yield. In addition, this method provided test data and a theoretical basis for high-value application of polypeptides from marine sources. [ABSTRACT FROM AUTHOR]

The human sense of taste is devoted to the analysis of the chemical composition of food prior to ingestion. Among the five basic taste qualities bitter taste perception is believed to avoid ingestion of potentially toxic substances. The receptors facilitating the detection of hundreds of chemically different bitter compounds belong to the taste 2 receptor (TAS2R) family, which are part of the G protein-coupled superfamily. Although the chemical classes of bitter compounds that have been identified as agonists of one of the 25 potentially functional human bitter taste receptors cover an enormous chemical space, one distinct group of bitter compounds, the bitter salts have not been assigned to any bitter taste receptor. To close this gap, we screened the entire human bitter taste receptor repertoire by functional calcium mobilization assays with the most famous bitter salt, magnesium sulfate, also known as Epsom salt. Although the profound pharmacological activity and the bitter taste of spring water containing magnesium sulfate has been known since 1697, the molecular basis for its taste has not been elucidated until now. Our screening resulted in the identification of a single receptor, the TAS2R7, responding to magnesium sulfate at concentrations humans perceive this salt as bitter. Subsequently, TAS2R7 was stimulated with other salts and it was found that this receptor also responds to manganese2+ and iron2+ ions, but not to potassium ions. Magnesium sulfate is known to exert a number of beneficial effects on the human body and thus, has been used as medicine against premature uterine contractions, as anti-arrhythmic drug and as laxative, however, magnesium sulfate overdosage can result in cardiac arrest and thus have fatal consequences. Therefore, it appears reasonable that nature placed TAS2R7 as sentinel for high concentrations of bitter salts on our tongues. • The human bitter taste receptor TAS2R7 responds to bitter salts. • Bitter salts have profound pharmacological activity and thus, require oral monitoring. • Magnesium sulfate concentrations activating TAS2R7 match human perception. • Manganese and iron ions also activate TAS2R7, however, potassium ions do not. • The anions sulfate and chloride do not contribute to TAS2R7 activation. [ABSTRACT FROM AUTHOR]

Among the nine voltage-gated sodium channel (NaV) subtypes, NaV1.8 is an attractive therapeutic target for pain. The heterologous expression of recombinant NaV1.8 currents is of particular importance for its electrophysiological and pharmacological studies. However, NaV1.8 expresses no or low-level functional currents when transiently transfected into non-neuronal cell lines. The present study aims to explore the molecular determinants limiting its functional expression and accordingly establish a functional NaV1.8 expression system. We conducted screening analysis of the NaV1.8 intracellular loops by constructing NaV chimeric channels and confirmed that the NaV1.8 C-terminus was the only limiting factor. Replacing this sequence with that of NaV1.4, NaV1.5, or NaV1.7 constructed functional channels (NaV1.8/1.4L5, NaV1.8/1.5L5, and NaV1.8/1.7L5, respectively), which expressed high-level NaV1.8-like currents in HEK293T cells. The chimeric channel NaV1.8/1.7L5 displayed much faster inactivation of its macroscopic currents than NaV1.8/1.4L5 and NaV1.8/1.5L5, and it was the most similar to wild-type NaV1.8 expressed in ND7/23 cells. Its currents were very stable during repetitive depolarizations, while its repriming kinetic was different from wild-type NaV1.8. Most importantly, NaV1.8/1.7L5 pharmacologically resembled wild-type NaV1.8 as revealed by testing their susceptibility to two NaV1.8 selective antagonists, APETx-2 and MrVIB. NaV chimeras study showed that at least the domain 2 and domain 4 of NaV1.8 were involved in binding with APETx-2. Our study provided new insights into the function of NaV1.8 intracellular loops, as well as a reliable and convenient expression system which could be useful in NaV1.8 studies.

The present study aimed to evaluate the functional expression of tree sinusiae in three sectors of a forest fragment in relation to different land use histories. The study recorded the number of individuals, number of individuals with multiple stems and number of tillers, calculated the percentages of tillered individuals and species, and then classified the species into regeneration and dispersal guilds. The most anthropised sector of the forest showed higher tillering and a larger proportion of pioneer and light-demanding climax species. The sector with moderate anthropisation presented intermediate tillering and mixed occurrence of light-demanding and shade-tolerant guilds. The non-anthropised sector showed lower tillering and a higher number of shade-tolerant species. The distribution of zoochorous individuals was not significant. In conclusion, the different levels of anthropisation provided distinct patterns of tillering and different compositions in regeneration guilds, highlighting their influence on the ecology of tropical forests. [ABSTRACT FROM AUTHOR]

Plants possess very large numbers of biosynthetic cytochrome P450 enzymes. In spite of the importance of these enzymes for the synthesis of bioactive plant secondary metabolites, only two plant P450 structures has been obtained to date. Isoflavone synthase (IFS) is a membrane-associated cytochrome P450 enzyme catalyzing the entry-point reaction into isoflavonoid biosynthesis. IFS from the model legume Medicago truncatula (CYP93C20) was engineered by deleting the membrane-spanning domain and inserting a hydrophilic polypeptide in the N-terminus and a four histidine tag at the C-terminus. The truncated form exhibited dramatically enhanced expression and solubility. The engineered enzyme was expressed in Escherichia coli XL1-blue cells and was purified by Ni 2+ -NTA affinity chromatograph and size-exclusion chromatograph. The purified enzyme was characterized by enzyme assay, reduced carbon monoxide difference spectroscopy and peptide mass fingerprinting. The engineered soluble enzyme exhibited the same activity as the full length membrane-associated enzyme expressed in yeast. These studies suggest an approach for engineering plant membrane-associated P450s with enhanced expression and solubility for mechanistic and structural studies. [ABSTRACT FROM AUTHOR]

Abstract: Aryl‐alcohol oxidase (AAO) plays a fundamental role in the fungal ligninolytic secretome, acting as a supplier of H2O2. Despite its highly selective mechanism of action, the presence of this flavooxidase in different biotechnological settings has hitherto been hampered by the lack of appropriate heterologous expression systems. We recently described the functional expression of the AAO from Pleurotus eryngii in Saccharomyces cerevisiae by fusing a chimeric signal peptide (preαproK) and applying structure‐guided evolution. Here, we have obtained an AAO secretion variant that is readily expressed in S. cerevisiae and overproduced in Pichia pastoris. First, the functional expression of AAO in S. cerevisiae was enhanced through the in vivo shuffling of a panel of secretion variants, followed by the focused evolution of the preαproK peptide. The outcome of this evolutionary campaign—an expression variant that accumulated 4 mutations in the chimeric signal peptide, plus two mutations in the mature protein‐ showed 350‐fold improved secretion (4.5 mg/L) and was stable. This secretion mutant was cloned into P. pastoris and fermented in a fed‐batch bioreactor to enhance production to 25 mg/L. While both recombinant AAO from S. cerevisiae and P. pastoris were subjected to the same N‐terminal processing and had a similar pH activity profile, they differed in their kinetic parameters and thermostability. The strong glycosylation observed in the evolved AAO from S. cerevisiae underpinned this effect, since when the mutant was produced in the glycosylation‐deficient S. cerevisiae strain Δkre2, its kinetic parameters and thermostability were comparable to its poorly glycosylated P. pastoris recombinant counterpart. [ABSTRACT FROM AUTHOR]

Among the nine voltage-gated sodium channel (NaV) subtypes, NaV1.8 is an attractive therapeutic target for pain. The heterologous expression of recombinant NaV1.8 currents is of particular importance for its electrophysiological and pharmacological studies. However, NaV1.8 expresses no or low-level functional currents when transiently transfected into non-neuronal cell lines. The present study aims to explore the molecular determinants limiting its functional expression and accordingly establish a functional NaV1.8 expression system. We conducted screening analysis of the NaV1.8 intracellular loops by constructing NaV chimeric channels and confirmed that the NaV1.8 C-terminus was the only limiting factor. Replacing this sequence with that of NaV1.4, NaV1.5, or NaV1.7 constructed functional channels (NaV1.8/1.4L5, NaV1.8/1.5L5 and NaV1.8/1.7L5, respectively), which expressed high-level NaV1.8-like currents in HEK293T cells. The chimeric channel NaV1.8/1.7L5 displayed much faster inactivation of its macroscopic currents than NaV1.8/1.4L5 and NaV1.8/1.5L5 and it was the most similar to wild-type NaV1.8 expressed in ND7/23 cells. Its currents were very stable during repetitive depolarizations, while its repriming kinetic was different from wildtype NaV1.8. Most importantly, NaV1.8/1.7L5 pharmacologically resembled wild-type NaV1.8 as revealed by testing their susceptibility to two NaV1.8 selective antagonists, APETx-2 and MrVIB. NaV chimeras study showed that at least the domain 2 and domain 4 of NaV1.8 were involved in binding with APETx-2. Our study provided new insights into the function of NaV1.8 intracellular loops, as well as a reliable and convenient expression system which could be useful in NaV1.8 studies. [ABSTRACT FROM AUTHOR]

We investigated the molecular and biochemical properties of two acetylcholinesterases (FoAChE1 and FoAChE2) from the Western flower thrips, Frankliniella occidentalis. Polyacrylamide gel electrophoresis and western blotting confirmed the membrane-anchored nature of both FoAChE1 and FoAChE2, which was further supported by hydrophobicity and glycophosphatidylinositol anchor predictions. High expression levels of both enzymes were observed in the head, indicating their predominant distribution in neuronal tissues. FoAChE1 exhibited significantly higher expression levels in all examined tissues compared to FoAChE2, suggesting its major role as a synaptic enzyme. Nonetheless, both recombinant enzymes displayed robust catalytic activity toward acetylthiocholine iodide, and FoAChE1 demonstrated nearly identical catalytic efficiency compared to FoAChE2. FoAChE1 exhibited slightly lower sensitivities to the cholinesterase inhibitors tested, including organophosphates (OPs) and carbamates (CBs), compared to FoAChE2. Field populations of F. occidentalis exhibited polymorphism of alanine vs. serine at position 197 of FoAChE1 within the conserved oxyanion hole. Contrary to common belief, however, functional analysis using recombinant enzymes revealed that neither A197 nor S197 residue was associated with FoAChE1 insensitivity to OPs and CBs. FoAChE2 did not exhibit any polymorphic amino acid substitutions at the positions known to be associated with resistance. Due to the absence of apparent resistance-associated mutations in field populations of F. occidentalis , the judicious use of some OPs or CBs can be suggested for controlling the highly resistant populations to other insecticides. Overall, our findings highlight the significance of both FoAChE1 and FoAChE2 as targets for toxicity assessment, while the specific contribution of each enzyme to toxicity remains unclear. [Display omitted] • Both FoAChE1 and FoAChE2 exist in membrane anchored forms. • FoAChE1 is the main synaptic enzyme. • The catalytic activity might be mostly originated from FoAChE1. • FoAChE1 showed slightly lower sensitivities to cholinesterase inhibitors compared to FoAChE2. • Neither the A197 nor S197 residue was associated with FoAChE1 insensitivity to OPs and CBs. [ABSTRACT FROM AUTHOR]

Bacterial laccases are potential enzymes for biotechnological applications, such as detoxification of industrial effluents, decolorization of textile, and dimerization of phenolic acids, due to their remarkable advantages, including broad substrate spectrum, high thermostability, wide pH scope, and tolerance to alkaline environments. L386W/G417L/G57F (abbreviated as WLF), a good mutant of CotA-laccase from Bacillus pumilus W3, has been constructed and reported by our laboratory with highly improved catalytic efficiency. However, the low-functional expression level of mutant WLF in Escherichia coli was a shortcoming. Three mutants, namely, K317N/WLF, D501G/WLF, and K317N/D501G/WLF, were constructed through site-directed mutagenesis to improve the functional expression of WLF in this study. The soluble and active expression of D501G/WLF and K317N/D501G/WLF in E. coli enhanced 4.48-fold and 3.63-fold level, respectively. The K317N/WLF failed to increase the soluble expression level, but slightly improved the stability of CotA-laccase. Results showed that not only the position 501 is significant for functional expression of B. pumilus W3 CotA, but also these mutants still remained its high thermostability, resistance of alkaline with salt, and conspicuous decolorizing efficiency. This work is the first to improve the soluble expression of B. pumilus CotA-laccase in E. coli by site-directed mutagenesis. The D501G/WLF and K317N/D501G/WLF will be suitable candidates for biotechnological applications. [ABSTRACT FROM AUTHOR]