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Neema KN, Hamse Kameshwar V, Nafeesa Z, Kumar D, Babu Shubha P, Nagendra Prasad MN, Swamy SN. Serine protease from Indian Cobra venom: its anticoagulant property and effect on human fibrinogen. TOXIN REV 2020. [DOI: 10.1080/15569543.2020.1855656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- K. N. Neema
- Department of Biotechnology, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, JSS Institutions Campus, Mysuru, Karnataka, India
- JSS Research Foundation, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, JSS Institutions Campus, Mysuru, Karnataka, India
| | - Vivek Hamse Kameshwar
- Department of Biotechnology, School of Natural Sciences, Adichunchanagiri University-Centre for Research and Innovation, Adichunchanagiri University, Nagamangala, Karnataka, India
| | - Zohara Nafeesa
- Department of Biotechnology, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, JSS Institutions Campus, Mysuru, Karnataka, India
- JSS Research Foundation, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, JSS Institutions Campus, Mysuru, Karnataka, India
| | - Divya Kumar
- Department of Biotechnology, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, JSS Institutions Campus, Mysuru, Karnataka, India
- JSS Research Foundation, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, JSS Institutions Campus, Mysuru, Karnataka, India
| | - Priya Babu Shubha
- Department of Studies in Chemistry, University of Mysore, Manasagangothri, Mysuru, Karnataka, India
| | - M. N. Nagendra Prasad
- Department of Biotechnology, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, JSS Institutions Campus, Mysuru, Karnataka, India
| | - Shivananju Nanjunda Swamy
- Department of Biotechnology, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, JSS Institutions Campus, Mysuru, Karnataka, India
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Barua A, Mikheyev AS. Many Options, Few Solutions: Over 60 My Snakes Converged on a Few Optimal Venom Formulations. Mol Biol Evol 2020; 36:1964-1974. [PMID: 31220860 PMCID: PMC6736290 DOI: 10.1093/molbev/msz125] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Gene expression changes contribute to complex trait variations in both individuals and populations. However, the evolution of gene expression underlying complex traits over macroevolutionary timescales remains poorly understood. Snake venoms are proteinaceous cocktails where the expression of each toxin can be quantified and mapped to a distinct genomic locus and traced for millions of years. Using a phylogenetic generalized linear mixed model, we analyzed expression data of toxin genes from 52 snake species spanning the 3 venomous snake families and estimated phylogenetic covariance, which acts as a measure of evolutionary constraint. We find that evolution of toxin combinations is not constrained. However, although all combinations are in principle possible, the actual dimensionality of phylomorphic space is low, with envenomation strategies focused around only four major toxin families: metalloproteases, three-finger toxins, serine proteases, and phospholipases A2. Although most extant snakes prioritize either a single or a combination of major toxin families, they are repeatedly recruited and lost. We find that over macroevolutionary timescales, the venom phenotypes were not shaped by phylogenetic constraints, which include important microevolutionary constraints such as epistasis and pleiotropy, but more likely by ecological filtering that permits a small number of optimal solutions. As a result, phenotypic optima were repeatedly attained by distantly related species. These results indicate that venoms evolve by selection on biochemistry of prey envenomation, which permit diversity through parallelism, and impose strong limits, since only a few of the theoretically possible strategies seem to work well and are observed in extant snakes.
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Affiliation(s)
- Agneesh Barua
- Okinawa Institute of Science and Technology Graduate University, Onna, Japan
| | - Alexander S Mikheyev
- Okinawa Institute of Science and Technology Graduate University, Onna, Japan.,Evolutionary Genomics Research Group, Ecology and Evolution Unit, Australian National University, Canberra, Australia
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Bittenbinder MA, Dobson JS, Zdenek CN, op den Brouw B, Naude A, Vonk FJ, Fry BG. Differential destructive (non-clotting) fibrinogenolytic activity in Afro-Asian elapid snake venoms and the links to defensive hooding behavior. Toxicol In Vitro 2019; 60:330-335. [DOI: 10.1016/j.tiv.2019.05.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 05/29/2019] [Accepted: 05/30/2019] [Indexed: 12/23/2022]
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Naja atra cardiotoxins enhance the protease activity of chymotrypsin. Int J Biol Macromol 2019; 136:512-520. [PMID: 31199971 DOI: 10.1016/j.ijbiomac.2019.06.066] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 05/27/2019] [Accepted: 06/11/2019] [Indexed: 02/03/2023]
Abstract
Snake venom cardiotoxins (CTXs) present diverse pharmacological functions. Previous studies have reported that CTXs affect the activity of some serine proteases, namely, chymotrypsin, subtilisin, trypsin, and acetylcholinesterase. To elucidate the mode of action of CTXs, the interaction of CTXs with chymotrypsin was thus investigated. It was found that Naja atra CTX isotoxins concentration-dependently enhanced chymotrypsin activity. The capability of CTX1 and CTX5 in increasing chymotrypsin activity was higher than that of CTX2, CTX3, and CTX4. Removal of the molecular beacon-bound CTXs by chymotrypsin, circular dichroism measurement, and acrylamide quenching of Trp fluorescence indicated that CTXs bound to chymotrypsin. Chemical modification of Lys, Arg, or Met residues of CTX1 attenuated its capability to enhance chymotrypsin activity without impairing their bond with chymotrypsin. Catalytically inactive chymotrypsin retained the binding affinity for native and modified CTX1. CTX1 and chemically modified CTX1 differently altered the global conformation of chymotrypsin and inactivated chymotrypsin. Moreover, CTX1 did not reduce the interaction of 2-(p-toluidino)-naphthalene-6-sulfonate (TNS) with chymotrypsin and inactivated chymotrypsin. Together with previous results revealing that TNS can bind at the hydrophobic region of active site in chymotrypsin, our data suggest that CTXs can enhance chymotrypsin activity by binding to the region outside the enzyme's active site.
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Yang ZM, Yu H, Liu ZZ, Pei JZ, Yang YE, Yan SX, Zhang C, Zhao WL, Wang ZZ, Wang YM, Tsai IH. Serine protease isoforms in Gloydius intermedius venom: Full sequences, molecular phylogeny and evolutionary implications. J Proteomics 2017; 164:19-32. [DOI: 10.1016/j.jprot.2017.05.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 05/18/2017] [Accepted: 05/25/2017] [Indexed: 02/07/2023]
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Comparison of proteomic profiles of the venoms of two of the 'Big Four' snakes of India, the Indian cobra (Naja naja) and the common krait (Bungarus caeruleus), and analyses of their toxins. Toxicon 2017; 135:33-42. [PMID: 28602829 DOI: 10.1016/j.toxicon.2017.06.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 06/06/2017] [Accepted: 06/07/2017] [Indexed: 11/20/2022]
Abstract
Snake venoms are mixtures of biologically-active proteins and peptides, and several studies have described the characteristics of some of these toxins. However, complete proteomic profiling of the venoms of many snake species has not yet been done. The Indian cobra (Naja naja) and common krait (Bungarus caeruleus) are elapid snake species that are among the 'Big Four' responsible for the majority of human snake envenomation cases in India. As understanding the composition and complexity of venoms is necessary for successful treatment of envenomation in humans, we utilized three different proteomic profiling approaches to characterize these venoms: i) one-dimensional SDS-PAGE coupled with in-gel tryptic digestion and electrospray tandem mass spectrometry (ESI-LC-MS/MS) of individual protein bands; ii) in-solution tryptic digestion of crude venoms coupled with ESI-LC-MS/MS; and iii) separation by gel-filtration chromatography coupled with tryptic digestion and ESI-LC-MS/MS of separated fractions. From the generated data, 81 and 46 different proteins were identified from N. naja and B. caeruleus venoms, respectively, belonging to fifteen different protein families. Venoms from both species were found to contain a variety of phospholipases A2 and three-finger toxins, whereas relatively higher numbers of snake venom metalloproteinases were found in N. naja compared to B. caeruleus venom. The analyses also identified less represented venom proteins including L-amino acid oxidases, cysteine-rich secretory proteins, 5'-nucleotidases and venom nerve growth factors. Further, Kunitz-type serine protease inhibitors, cobra venom factors, phosphodiesterases, vespryns and aminopeptidases were identified in the N. naja venom, while acetylcholinesterases and hyaluronidases were found in the B. caeruleus venom. We further analyzed protein coverage (Lys/Arg rich and poor regions as well as potential glycosylation sites) using in-house software. These studies expand our understanding of the proteomes of the venoms of these two medically-important species.
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Oliveira FDR, Noronha MDDN, Lozano JLL. Biological and molecular properties of yellow venom of the Amazonian coral snake Micrurus surinamensis. Rev Soc Bras Med Trop 2017; 50:365-373. [DOI: 10.1590/0037-8682-0408-2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 04/11/2017] [Indexed: 11/22/2022] Open
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Urra FA, Pulgar R, Gutiérrez R, Hodar C, Cambiazo V, Labra A. Identification and molecular characterization of five putative toxins from the venom gland of the snake Philodryas chamissonis (Serpentes: Dipsadidae). Toxicon 2015; 108:19-31. [PMID: 26410112 DOI: 10.1016/j.toxicon.2015.09.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 09/20/2015] [Accepted: 09/21/2015] [Indexed: 12/01/2022]
Abstract
Philodryas chamissonis is a rear-fanged snake endemic to Chile. Its bite produces mild to moderate symptoms with proteolytic and anti-coagulant effects. Presently, the composition of the venom, as well as, the biochemical and structural characteristics of its toxins, remains unknown. In this study, we cloned and reported the first full-length sequences of five toxin-encoding genes from the venom gland of this species: Type III snake venom metalloprotease (SVMP), snake venom serine protease (SVSP), Cysteine-rich secretory protein (CRISP), α and β subunits of C-type lectin-like protein (CLP) and C-type natriuretic peptide (NP). These genes are highly expressed in the venom gland and their sequences exhibited a putative signal peptide, suggesting that these are components of the venom. These putative toxins had different evolutionary relationships with those reported for some front-fanged snakes, being SVMP, SVSP and CRISP of P. chamissonis closely related to the toxins present in Elapidae species, while NP was more related to those of Viperidae species. In addition, analyses suggest that the α and β subunits of CLP of P. chamissonis might have a α-subunit scaffold in common with Viperidae species, whose highly variable C-terminal region might have allowed the diversification in α and β subunits. Our results provide the first molecular description of the toxins possibly implicated in the envenomation of prey and humans by the bite of P. chamissonis.
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Affiliation(s)
- Félix A Urra
- Laboratorio de Neuroetología, Programa de Fisiología y Biofísica, Facultad de Medicina, Universidad de Chile, Casilla 70005, Correo 7, Santiago, Chile; Laboratorio de Cáncer y Bioenergética, Programa de Farmacología Molecular y Clínica, Facultad de Medicina, Universidad de Chile, Casilla 70005, Correo 7, Santiago, Chile.
| | - Rodrigo Pulgar
- Laboratorio de Bioinformática y Expresión Génica, INTA, Universidad de Chile and Fondap Center for Genome Regulation (CGR), El Líbano 5524, Santiago, Chile
| | - Ricardo Gutiérrez
- Laboratorio de Bioinformática y Expresión Génica, INTA, Universidad de Chile and Fondap Center for Genome Regulation (CGR), El Líbano 5524, Santiago, Chile
| | - Christian Hodar
- Laboratorio de Bioinformática y Expresión Génica, INTA, Universidad de Chile and Fondap Center for Genome Regulation (CGR), El Líbano 5524, Santiago, Chile
| | - Verónica Cambiazo
- Laboratorio de Bioinformática y Expresión Génica, INTA, Universidad de Chile and Fondap Center for Genome Regulation (CGR), El Líbano 5524, Santiago, Chile
| | - Antonieta Labra
- Laboratorio de Neuroetología, Programa de Fisiología y Biofísica, Facultad de Medicina, Universidad de Chile, Casilla 70005, Correo 7, Santiago, Chile; Department of Biosciences, Centre for Ecological and Evolutionary Synthesis, University of Oslo, PB1066 Blinder, 0316 Oslo, Norway.
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Gao JF, Wang J, Qu YF, Ma XM, Ji X. Immunoreactivity between venoms and commercial antiserums in four Chinese snakes and venom identification by species-specific antibody. J Immunol Methods 2012; 387:211-8. [PMID: 23142457 DOI: 10.1016/j.jim.2012.10.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Revised: 10/02/2012] [Accepted: 10/31/2012] [Indexed: 11/17/2022]
Abstract
We studied the immunoreactivity between venoms and commercial antiserums in four Chinese venomous snakes, Bungarus multicinctus, Naja atra, Deinagkistrodon acutus and Gloydius brevicaudus. Venoms from the four snakes shared common antigenic components, and most venom components expressed antigenicity in the immunological reaction between venoms and antiserums. Antiserums cross-reacted with heterologous venoms. Homologous venom and antiserum expressed the highest reaction activity in all cross-reactions. Species-specific antibodies (SSAbs) were obtained from four antiserums by immunoaffinity chromatography: the whole antiserum against each species was gradually passed through a medium system coated with heterologous venoms, and the cross-reacting components in antiserum were immunoabsorbed by the common antigens in heterologous venoms; the unbound components (i.e., SSAbs) were collected, and passed through Hitrap G protein column and concentrated. The SSAbs were found to have high specificity by western blot and enzyme-linked immunosorbent assay (ELISA). A 6-well ELISA strip coated with SSAbs was used to assign a venom sample and blood and urine samples from the envenomed rats to a given snake species. Our detections could differentiate positive and negative samples, and identify venoms of a snake species in about 35 min. The ELISA strips developed in this study are clinically useful in rapid and reliable identification of venoms from the above four snake species.
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Affiliation(s)
- Jian-Fang Gao
- Hangzhou Key Laboratory for Animal Adaptation and Evolution, School of Life Sciences, Hangzhou Normal University, Hangzhou, 310036 Zhejiang, China
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Yang L, Tang Z, Liu W, Xiao J, Hu S, Yang L, Liu W, Deng H, Feng Q. Evolutional and functional analysis of a serine protease in Spodoptera litura. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2012; 81:121-135. [PMID: 22930521 DOI: 10.1002/arch.21049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Spodoptera litura is a threatening agricultural insect in tropical and subtropical areas and accounts for tremendous annual crop losses. As seen in virtually all insect species, serine proteases (SPs) are crucial to S. litura. The expression pattern of SPs from the midgut of S. litura was studied through expressed sequence tags (ESTs) analysis. One of SP (SlSP1) was chosen for detailed study, because the expression of the gene was midgut and larvae specific. SlSP1 was conducted as a model of its evolution, structure, and potential binding activity with corresponding substrates. SlSP1 is composed of 255 amino acids including a signal peptide at N-terminal followed by a putative activation peptide and the mature protein along with five putative phosphorylation sites, three disulphide bridges, and two N-glycosylation positions. At least nine conserved motifs were obtained in multiple sequence alignments. Some conserved residues, such as the catalytic triad His84, Asp127, and Ser229 as well as six cysteines at position 66, 82, 194, 211, 223, and 247, were examined. After homology modeling and molecular dynamics simulation, the resultant three-dimensional (3D) structure of SlSP1 was docked with the substrates 2PTC-Arg and 2PTC-Lys, respectively. Molecular Mechanic/Poisson-Boltzmann surface area analysis was applied to anticipate optimal binding mode and crucial active sites of this enzyme. The residues Trp28, Gly187, Aso188, Arg249, Ile250, Lys246, and Lys278 are crucial for the substrate binding and molecule process. This information can be used in logical design of SPs inhibitors. New inhibitors may be a basis for development of a new pest control technology.
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Affiliation(s)
- Li Yang
- Natural Products Research Center, Chengdu Institute of Biology, Chinese Academy of Science, Chengdu, China
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Wang Y, Xu W, Kou X, Luo Y, Zhang Y, Ma B, Wang M, Huang K. Establishment and optimization of a wheat germ cell-free protein synthesis system and its application in venom kallikrein. Protein Expr Purif 2012; 84:173-80. [PMID: 22626528 DOI: 10.1016/j.pep.2012.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 05/10/2012] [Accepted: 05/14/2012] [Indexed: 12/18/2022]
Abstract
Wheat germ cell-free protein synthesis systems have the potential to synthesize functional proteins safely and with high accuracy, but the poor energy supply and the instability of mRNA templates reduce the productivity of this system, which restricts its applications. In this report, phosphocreatine and pyruvate were added to the system to supply ATP as a secondary energy source. After comparing the protein yield, we found that phosphocreatine is more suitable for use in the wheat germ cell-free protein synthesis system. To stabilize the mRNA template, the plasmid vector, SP6 RNA polymerase, and Cu(2+) were optimized, and a wheat germ cell-free protein synthesis system with high yield and speed was established. When plasmid vector (30 ng/μl), SP6 RNA polymerase (15 U), phosphocreatine (25 mM), and Cu(2+) (5 mM) were added to the system and incubated at 26°C for 16 h, the yield of venom kallikrein increased from 0.13 to 0.74 mg/ml. The specific activity of the recombinant protein was 1.3 U/mg, which is only slightly lower than the crude venom kallikrein (1.74 U/mg) due to the lack of the sugar chain. In this study, the yield of venom kallikrein was improved by optimizing the system, and a good foundation has been laid for industrial applications and for further studies.
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Affiliation(s)
- Yunpeng Wang
- School of Chemical Engineering and Technology, Tianjin University Tianjin 300072, China
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Sukkapan P, Jia Y, Nuchprayoon I, Pérez JC. Phylogenetic analysis of serine proteases from Russell's viper (Daboia russelli siamensis) and Agkistrodon piscivorus leucostoma venom. Toxicon 2011; 58:168-78. [PMID: 21640745 PMCID: PMC3303153 DOI: 10.1016/j.toxicon.2011.05.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 05/17/2011] [Accepted: 05/19/2011] [Indexed: 10/18/2022]
Abstract
Serine proteases are widely found in snake venoms. They have variety of functions including contributions to hemostasis. In this study, five serine proteases were cloned and characterized from two different cDNA libraries: factor V activator (RVV-V), alpha fibrinogenase (RVAF) and beta fibrinogenase (RVBF) from Russell's viper (Daboia russelli siamensis), and plasminogen activator (APL-PA) and protein C activator (APL-C) from Agkistrodon piscivorus leucostoma. The snake venom serine proteases were clustered in phylogenetic tree according to their functions. K(A)/K(S) values suggested that accelerated evolution has occurred in the mature protein coding regions in cDNAs of snake venom serine proteases.
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Affiliation(s)
- Pattadon Sukkapan
- Snake Bite and Venom Research Unit, Chula Medical Research Center, Faculty of Medicine, Chulalongkorn University, Rama IV Road, Patumwan District, Bangkok 10330, Thailand
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Lu QM, Lai R, Zhang Y. [Animal toxins and human disease: from single component to venomics, from biochemical characterization to disease mechanisms, from crude venom utilization to rational drug design]. DONG WU XUE YAN JIU = ZOOLOGICAL RESEARCH 2010; 31:2-16. [PMID: 20446448 DOI: 10.3724/sp.j.1141.2010.01002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Many animals produced a diversity of venoms and secretions to adapt the changes of environments through the long history of evolution. The components including a large quantity of specific and highly active peptides and proteins have become good research models for protein structure-function and also served as tools and novel clues for illustration of human disease mechanisms. At the same time, they are rich natural resources for new drug development. Through the valuable venomous animal resources of China, researchers at the Kunming Institute of Zoology, CAS have carried out animal toxin research over 30 years. This paper reviews the main work conducted on snake venoms, amphibian and insect secretions, and the development from single component to venomics, from biochemical characterization to human disease mechanisms, from crude venom to rational drug design along with a short perspective on future studies.
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Affiliation(s)
- Qiu-Min Lu
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming 650223, China
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Liu S, Sun MZ, Sun C, Zhao B, Greenaway FT, Zheng Q. A novel serine protease from the snake venom of Agkistrodon blomhoffii ussurensis. Toxicon 2008; 52:760-8. [PMID: 18817802 PMCID: PMC2845635 DOI: 10.1016/j.toxicon.2008.08.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 07/26/2008] [Accepted: 08/20/2008] [Indexed: 10/21/2022]
Abstract
A novel serine protease, ABUSV-SPase, was isolated to homogeneity for the first time from Chinese Agkistrodon blomhoffii ussurensis snake venom, and its enzymatic and structural properties were characterized by multiple techniques. ABUSV-SPase is a stable monomeric protein with a molecular mass of 26,752.6a.m.u. It reacts optimally with its substrate Nalpha-tosyl-l-arginine methyl ester (TAME) at pH 7.0 and 41 degrees C. ESI-MS/MS analysis indicates that ABUSV-SPase is a new serine protease, sharing peptide homologies with various snake venom serine proteases, especially the snake venom thrombin-like enzymes of this group, and serine protease precursors. It is a zinc-containing protein, and although zinc is not essential for activity, its replacement by various divalent metal ions, including Mg2+, Mn2+, and Ca2+, increases the TAME hydrolysis activity of the enzyme. The intrinsic fluorescences of Tyr and Trp residues of ABUSV-SPase have emission wavelengths red-shifted by 12.8nm and 3.6nm from those of free Tyr and Trp, respectively. The zinc ion increases the hydrophobicity of the environment of the Trp residues, increases the thermostability of the protein, and affects the protein secondary structure to stabilize the enzyme, but appears to have no direct role in its esterase hydrolysis activity.
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Affiliation(s)
- Shuqing Liu
- Department of Biochemistry, Dalian Medical University, Dalian 116044, PR China
| | - Ming-Zhong Sun
- Department of Biotechnology, Dalian Medical University, 9 West Lvshun South Road, Dalian, Liaoning 116044, PR China
| | - Changkai Sun
- Department of Physiology, Dalian Medical University, Dalian 116044, PR China
| | - Baochang Zhao
- Department of Biochemistry, Dalian Medical University, Dalian 116044, PR China
| | - Frederick T. Greenaway
- Carlson School of Chemistry and Biochemistry, Clark University, Worcester, MA 01610, USA
| | - Qingyin Zheng
- Department of Otolaryngology–HNS, Case Western Reserve University, Cleveland, OH 44106, USA
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