1
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Liu CC, Hsiao YC, Lai WJ, Chiou CC, Chu LJ, Lin YT, Liu JC, Yu JS. Development and optimization of a DNA aptamer to delay β-bungarotoxin-induced lethality in a rodent model. Int J Biol Macromol 2024; 270:132240. [PMID: 38744360 DOI: 10.1016/j.ijbiomac.2024.132240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/18/2024] [Accepted: 05/07/2024] [Indexed: 05/16/2024]
Abstract
Current treatment of snakebite relies on immunoglobulin-rich antivenoms. However, production of these antivenoms is complicated and costly. Aptamers - single-stranded DNAs or RNAs with specific folding structures that bind to specific target molecules - represent excellent alternatives or complements to antibody-based therapeutics. However, no studies have systematically assessed the feasibility of using aptamers to mitigate venom-induced toxicity in vivo. β-bungarotoxin is the predominant protein responsible for the toxicity of the venom of Bungarus multicinctus, a prominent venomous snake inhabiting Taiwan. In this study, we reported the screening and optimization of a DNA aptamer against β-bungarotoxin and tested its utility in a mouse model. After 14 rounds of directed evolution of ligands by exponential enrichment, an aptamer, called BB3, displaying remarkable binding affinity and specificity for β-bungarotoxin was obtained. Following structural prediction and point-modification experiments, BB3 underwent truncation and was modified with 2'-O-methylation and a 3'-inverted dT. This optimized aptamer showed sustained, high-affinity binding for β-bungarotoxin and exhibited remarkable nuclease resistance in plasma. Importantly, administration of this optimized aptamer extended the survival time of mice treated with a lethal dose of β-bungarotoxin. Collectively, our data provide a compelling illustration of the potential of aptamers as promising candidates for development of recombinant antivenom therapies.
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Affiliation(s)
- Chien-Chun Liu
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan
| | - Yung-Chin Hsiao
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan; Department of Otolaryngology-Head and Neck Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan
| | - Wan-Jing Lai
- College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Chiuan-Chian Chiou
- Master & PhD Program in Biotechnology Industry, Chang Gung University, Taoyuan 33302, Taiwan
| | - Lichieh Julie Chu
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan; Department of Otolaryngology-Head and Neck Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan
| | - Yu-Tsun Lin
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan
| | - Jo-Chuan Liu
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan
| | - Jau-Song Yu
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan; Department of Otolaryngology-Head and Neck Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan; Research Center for Food and Cosmetic Safety, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan 33302, Taiwan.
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2
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Liu CC, Lin CC, Liou MH, Hsiao YC, Chu LJ, Wang PJ, Liu CH, Wang CY, Chen CH, Yu JS. Development of antibody-detection ELISA based on beta-bungarotoxin for evaluation of the neutralization potency of equine plasma against Bungarus multicinctus in Taiwan. Int J Biol Macromol 2024; 262:130080. [PMID: 38354918 DOI: 10.1016/j.ijbiomac.2024.130080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 01/17/2024] [Accepted: 02/08/2024] [Indexed: 02/16/2024]
Abstract
Animal testing has been the primary approach to assess the neutralization potency of antivenom for decades. However, the necessity to sacrifice large numbers of experimental animals during this process has recently raised substantial welfare concerns. Furthermore, the laborious and expensive nature of animal testing highlights the critical need to develop alternative in vitro assays. Here, we developed an antibody-detection enzyme-linked immunosorbent assay (ELISA) technique as an alternative approach to evaluate the neutralization potency of hyperimmunized equine plasma against B. multicinctus, a medically important venomous snake in Taiwan. Firstly, five major protein components of B. multicinctus venom, specifically, α-BTX, β-BTX, γ-BTX, MTX, and NTL, were isolated. To rank their relative medical significance, a toxicity score system was utilized. Among the proteins tested, β-BTX presenting the highest score was regarded as the major toxic component. Subsequently, antibody-detection ELISA was established based on the five major proteins and used to evaluate 55 hyperimmunized equine plasma samples with known neutralization potency. ELISA based on β-BTX, the most lethal protein according to the toxicity score, exhibited the best sensitivity (75.6 %) and specificity (100 %) in discriminating between high-potency and low-potency plasma, supporting the hypothesis that highly toxic proteins offer better discriminatory power for potency evaluation. Additionally, a phospholipase A2 (PLA2) competition process was implemented to eliminate the antibodies targeting toxicologically irrelevant domains. This optimization greatly enhanced the performance of our assay, resulting in sensitivity of 97.6 % and specificity of 92.9 %. The newly developed antibody-detection ELISA presents a promising alternative to in vivo assays to determine the neutralization potency of antisera against B. multicinctus during the process of antivenom production.
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Affiliation(s)
- Chien-Chun Liu
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan
| | - Chih-Chuan Lin
- Department of Emergency Medicine, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan
| | - Ming-Han Liou
- College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Yung-Chin Hsiao
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan; Liver Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan
| | - Lichieh Julie Chu
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan; Liver Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan
| | - Po-Jung Wang
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan
| | - Chien-Hsin Liu
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei 11561, Taiwan
| | - Cyong-Yi Wang
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei 11561, Taiwan
| | - Chao-Hung Chen
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei 11561, Taiwan
| | - Jau-Song Yu
- Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan; Research Center for Food and Cosmetic Safety, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan 33302, Taiwan; Department of Otolaryngology-Head and Neck Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan..
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3
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Albulescu LO, Westhorpe A, Clare RH, Woodley CM, James N, Kool J, Berry NG, O’Neill PM, Casewell NR. Optimizing drug discovery for snakebite envenoming via a high-throughput phospholipase A2 screening platform. Front Pharmacol 2024; 14:1331224. [PMID: 38273832 PMCID: PMC10808766 DOI: 10.3389/fphar.2023.1331224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/19/2023] [Indexed: 01/27/2024] Open
Abstract
Snakebite envenoming is a neglected tropical disease that causes as many as 1.8 million envenomings and 140,000 deaths annually. To address treatment limitations that exist with current antivenoms, the search for small molecule drug-based inhibitors that can be administered as early interventions has recently gained traction. Snake venoms are complex mixtures of proteins, peptides and small molecules and their composition varies substantially between and within snake species. The phospholipases A2 (PLA2) are one of the main pathogenic toxin classes found in medically important viper and elapid snake venoms, yet varespladib, a drug originally developed for the treatment of acute coronary syndrome, remains the only PLA2 inhibitor shown to effectively neutralise venom toxicity in vitro and in vivo, resulting in an extremely limited drug portfolio. Here, we describe a high-throughput drug screen to identify novel PLA2 inhibitors for repurposing as snakebite treatments. We present method optimisation of a 384-well plate, colorimetric, high-throughput screening assay that allowed for a throughput of ∼2,800 drugs per day, and report on the screening of a ∼3,500 post-phase I repurposed drug library against the venom of the Russell's viper, Daboia russelii. We further explore the broad-spectrum inhibitory potential and efficacy of the resulting top hits against a range of medically important snake venoms and demonstrate the utility of our method in determining drug EC50s. Collectively, our findings support the future application of this method to fully explore the chemical space to discover novel PLA2-inhibiting drugs of value for preventing severe pathology caused by snakebite envenoming.
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Affiliation(s)
- Laura-Oana Albulescu
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Adam Westhorpe
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Rachel H. Clare
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | - Nivya James
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - Jeroen Kool
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Neil G. Berry
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - Paul M. O’Neill
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - Nicholas R. Casewell
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Zhang P, Liu B, Mu X, Xu J, Du B, Wang J, Liu Z, Tong Z. Performance of Classification Models of Toxins Based on Raman Spectroscopy Using Machine Learning Algorithms. Molecules 2023; 29:197. [PMID: 38202780 PMCID: PMC10780255 DOI: 10.3390/molecules29010197] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 12/21/2023] [Accepted: 12/26/2023] [Indexed: 01/12/2024] Open
Abstract
Rapid and accurate detection of protein toxins is crucial for public health. The Raman spectra of several protein toxins, such as abrin, ricin, staphylococcal enterotoxin B (SEB), and bungarotoxin (BGT), have been studied. Multivariate scattering correction (MSC), Savitzky-Golay smoothing (SG), and wavelet transform methods (WT) were applied to preprocess Raman spectra. A principal component analysis (PCA) was used to extract spectral features, and the PCA score plots clustered four toxins with two other proteins. The k-means clustering results show that the spectra processed with MSC and MSC-SG methods have the best classification performance. Then, the two data types were classified using partial least squares discriminant analysis (PLS-DA) with an accuracy of 100%. The prediction results of the PCA and PLS-DA and the partial least squares regression model (PLSR) perform well for the fingerprint region spectra. The PLSR model demonstrates excellent classification and regression ability (accuracy = 100%, Rcv = 0.776). Four toxins were correctly classified with interference from two proteins. Classification models based on spectral feature extraction were established. This strategy shows excellent potential in toxin detection and public health protection. These models provide alternative paths for the development of rapid detection devices.
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Affiliation(s)
| | | | | | | | | | | | | | - Zhaoyang Tong
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China; (P.Z.); (B.L.); (X.M.); (J.X.); (B.D.); (J.W.); (Z.L.)
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5
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AlShammari AK, Abd El-Aziz TM, Al-Sabi A. Snake Venom: A Promising Source of Neurotoxins Targeting Voltage-Gated Potassium Channels. Toxins (Basel) 2023; 16:12. [PMID: 38251229 PMCID: PMC10820993 DOI: 10.3390/toxins16010012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 12/11/2023] [Accepted: 12/19/2023] [Indexed: 01/23/2024] Open
Abstract
The venom derived from various sources of snakes represents a vast collection of predominantly protein-based toxins that exhibit a wide range of biological actions, including but not limited to inflammation, pain, cytotoxicity, cardiotoxicity, and neurotoxicity. The venom of a particular snake species is composed of several toxins, while the venoms of around 600 venomous snake species collectively encompass a substantial reservoir of pharmacologically intriguing compounds. Despite extensive research efforts, a significant portion of snake venoms remains uncharacterized. Recent findings have demonstrated the potential application of neurotoxins derived from snake venom in selectively targeting voltage-gated potassium channels (Kv). These neurotoxins include BPTI-Kunitz polypeptides, PLA2 neurotoxins, CRISPs, SVSPs, and various others. This study provides a comprehensive analysis of the existing literature on the significance of Kv channels in various tissues, highlighting their crucial role as proteins susceptible to modulation by diverse snake venoms. These toxins have demonstrated potential as valuable pharmacological resources and research tools for investigating the structural and functional characteristics of Kv channels.
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Affiliation(s)
- Altaf K. AlShammari
- College of Engineering and Technology, American University of the Middle East, Egaila 54200, Kuwait;
| | - Tarek Mohamed Abd El-Aziz
- Zoology Department, Faculty of Science, Minia University, El-Minia 61519, Egypt
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Ahmed Al-Sabi
- College of Engineering and Technology, American University of the Middle East, Egaila 54200, Kuwait;
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Genomic, transcriptomic, and epigenomic analysis of a medicinal snake, Bungarus multicinctus, to provides insights into the origin of Elapidae neurotoxins. Acta Pharm Sin B 2022; 13:2234-2249. [DOI: 10.1016/j.apsb.2022.11.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/20/2022] [Accepted: 11/11/2022] [Indexed: 11/19/2022] Open
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7
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Urra FA, Vivas-Ruiz DE, Sanchez EF, Araya-Maturana R. An Emergent Role for Mitochondrial Bioenergetics in the Action of Snake Venom Toxins on Cancer Cells. Front Oncol 2022; 12:938749. [PMID: 35924151 PMCID: PMC9343075 DOI: 10.3389/fonc.2022.938749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Accepted: 06/14/2022] [Indexed: 01/09/2023] Open
Abstract
Beyond the role of mitochondria in apoptosis initiation/execution, some mitochondrial adaptations support the metastasis and chemoresistance of cancer cells. This highlights mitochondria as a promising target for new anticancer strategies. Emergent evidence suggests that some snake venom toxins, both proteins with enzymatic and non-enzymatic activities, act on the mitochondrial metabolism of cancer cells, exhibiting unique and novel mechanisms that are not yet fully understood. Currently, six toxin classes (L-amino acid oxidases, thrombin-like enzymes, secreted phospholipases A2, three-finger toxins, cysteine-rich secreted proteins, and snake C-type lectin) that alter the mitochondrial bioenergetics have been described. These toxins act through Complex IV activity inhibition, OXPHOS uncoupling, ROS-mediated permeabilization of inner mitochondrial membrane (IMM), IMM reorganization by cardiolipin interaction, and mitochondrial fragmentation with selective migrastatic and cytotoxic effects on cancer cells. Notably, selective internalization and direct action of snake venom toxins on tumor mitochondria can be mediated by cell surface proteins overexpressed in cancer cells (e.g. nucleolin and heparan sulfate proteoglycans) or facilitated by the elevated Δψm of cancer cells compared to that non-tumor cells. In this latter case, selective mitochondrial accumulation, in a Δψm-dependent manner, of compounds linked to cationic snake peptides may be explored as a new anti-cancer drug delivery system. This review analyzes the effect of snake venom toxins on mitochondrial bioenergetics of cancer cells, whose mechanisms of action may offer the opportunity to develop new anticancer drugs based on toxin scaffolds.
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Affiliation(s)
- Félix A. Urra
- Laboratorio de Plasticidad Metabólica y Bioenergética, Programa de Farmacología Clínica y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Network for Snake Venom Research and Drug Discovery, Santiago, Chile
- Interdisciplinary Group on Mitochondrial Targeting and Bioenergetics (MIBI), Talca, Chile
- *Correspondence: Félix A. Urra,
| | - Dan E. Vivas-Ruiz
- Network for Snake Venom Research and Drug Discovery, Santiago, Chile
- Laboratorio de Biología Molecular, Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos, Ciudad Universitaria, Lima, Peru
| | - Eladio Flores Sanchez
- Network for Snake Venom Research and Drug Discovery, Santiago, Chile
- Laboratory of Biochemistry of Proteins from Animal Venoms, Research and Development Center, Ezequiel Dias Foundation, Belo Horizonte, Brazil
| | - Ramiro Araya-Maturana
- Network for Snake Venom Research and Drug Discovery, Santiago, Chile
- Interdisciplinary Group on Mitochondrial Targeting and Bioenergetics (MIBI), Talca, Chile
- Laboratorio de Productos Bioactivos, Instituto de Química de Recursos Naturales, Universidad de Talca, Talca, Chile
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8
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Zhang ZY, Lv Y, Wu W, Yan C, Tang CY, Peng C, Li JT. The structural and functional divergence of a neglected three-finger toxin subfamily in lethal elapids. Cell Rep 2022; 40:111079. [PMID: 35830808 DOI: 10.1016/j.celrep.2022.111079] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 05/04/2022] [Accepted: 06/20/2022] [Indexed: 11/24/2022] Open
Abstract
Bungarus multicinctus is a widely distributed and medically important elapid snake that produces lethal neurotoxic venom. To study and enhance existing antivenom, we explore the complete repertoire of its toxin genes based on de novo chromosome-level assembly and multi-tissue transcriptome data. Comparative genomic analyses suggest that the three-finger toxin family (3FTX) may evolve through the neofunctionalization of flanking LY6E. A long-neglected 3FTX subfamily (i.e., MKA-3FTX) is also investigated. Only one MKA-3FTX gene, which evolves a different protein conformation, is under positive selection and actively transcribed in the venom gland, functioning as a major toxin effector together with MKT-3FTX subfamily homologs. Furthermore, this lethal snake may acquire self-resistance to its β-bungarotoxin via amino acid replacements on fast-evolving KCNA2. This study provides valuable resources for further evolutionary and structure-function studies of snake toxins, which are fundamental for the development of effective antivenoms and drug candidates.
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Affiliation(s)
- Zhi-Yi Zhang
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan 610041, China
| | - Yunyun Lv
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan 610041, China; College of Life Science, Neijiang Normal University, Neijiang, Sichuan 641100, China
| | - Wei Wu
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan 610041, China; University of Chinese Academy of Sciences, Beijing 101408, China
| | - Chaochao Yan
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan 610041, China
| | - Chen-Yang Tang
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan 610041, China
| | - Changjun Peng
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan 610041, China; University of Chinese Academy of Sciences, Beijing 101408, China
| | - Jia-Tang Li
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan 610041, China; University of Chinese Academy of Sciences, Beijing 101408, China; Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
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9
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Suranse V, Jackson TNW, Sunagar K. Contextual Constraints: Dynamic Evolution of Snake Venom Phospholipase A 2. Toxins (Basel) 2022; 14:toxins14060420. [PMID: 35737081 PMCID: PMC9231074 DOI: 10.3390/toxins14060420] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 11/25/2022] Open
Abstract
Venom is a dynamic trait that has contributed to the success of numerous organismal lineages. Predominantly composed of proteins, these complex cocktails are deployed for predation and/or self-defence. Many non-toxic physiological proteins have been convergently and recurrently recruited by venomous animals into their toxin arsenal. Phospholipase A2 (PLA2) is one such protein and features in the venoms of many organisms across the animal kingdom, including snakes of the families Elapidae and Viperidae. Understanding the evolutionary history of this superfamily would therefore provide insight into the origin and diversification of venom toxins and the evolution of novelty more broadly. The literature is replete with studies that have identified diversifying selection as the sole influence on PLA2 evolution. However, these studies have largely neglected the structural/functional constraints on PLA2s, and the ecology and evolutionary histories of the diverse snake lineages that produce them. By considering these crucial factors and employing evolutionary analyses integrated with a schema for the classification of PLA2s, we uncovered lineage-specific differences in selection regimes. Thus, our work provides novel insights into the evolution of this major snake venom toxin superfamily and underscores the importance of considering the influence of evolutionary and ecological contexts on molecular evolution.
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Affiliation(s)
- Vivek Suranse
- Evolutionary Venomics Laboratory, Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India;
| | - Timothy N. W. Jackson
- Australian Venom Research Unit, Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, VIC 3010, Australia;
| | - Kartik Sunagar
- Evolutionary Venomics Laboratory, Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India;
- Correspondence: ; Tel.: +91-080-2293-2895
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10
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Oliveira AL, Viegas MF, da Silva SL, Soares AM, Ramos MJ, Fernandes PA. The chemistry of snake venom and its medicinal potential. Nat Rev Chem 2022; 6:451-469. [PMID: 37117308 PMCID: PMC9185726 DOI: 10.1038/s41570-022-00393-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/26/2022] [Indexed: 12/15/2022]
Abstract
The fascination and fear of snakes dates back to time immemorial, with the first scientific treatise on snakebite envenoming, the Brooklyn Medical Papyrus, dating from ancient Egypt. Owing to their lethality, snakes have often been associated with images of perfidy, treachery and death. However, snakes did not always have such negative connotations. The curative capacity of venom has been known since antiquity, also making the snake a symbol of pharmacy and medicine. Today, there is renewed interest in pursuing snake-venom-based therapies. This Review focuses on the chemistry of snake venom and the potential for venom to be exploited for medicinal purposes in the development of drugs. The mixture of toxins that constitute snake venom is examined, focusing on the molecular structure, chemical reactivity and target recognition of the most bioactive toxins, from which bioactive drugs might be developed. The design and working mechanisms of snake-venom-derived drugs are illustrated, and the strategies by which toxins are transformed into therapeutics are analysed. Finally, the challenges in realizing the immense curative potential of snake venom are discussed, and chemical strategies by which a plethora of new drugs could be derived from snake venom are proposed.
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Affiliation(s)
- Ana L Oliveira
- Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal.,LAQV/Requimte, University of Porto, Porto, Portugal
| | - Matilde F Viegas
- Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal.,LAQV/Requimte, University of Porto, Porto, Portugal
| | - Saulo L da Silva
- Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal.,LAQV/Requimte, University of Porto, Porto, Portugal
| | - Andreimar M Soares
- Biotechnology Laboratory for Proteins and Bioactive Compounds from the Western Amazon, Oswaldo Cruz Foundation, National Institute of Epidemiology in the Western Amazon (INCT-EpiAmO), Porto Velho, Brazil.,Sao Lucas Universitary Center (UniSL), Porto Velho, Brazil
| | - Maria J Ramos
- Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal.,LAQV/Requimte, University of Porto, Porto, Portugal
| | - Pedro A Fernandes
- Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal.,LAQV/Requimte, University of Porto, Porto, Portugal
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11
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Karim S, Kumar D, Adamson S, Ennen JR, Qualls CP, Ribeiro JMC. The sialotranscriptome of the gopher-tortoise tick, Amblyomma tuberculatum. Ticks Tick Borne Dis 2020; 12:101560. [PMID: 33007669 DOI: 10.1016/j.ttbdis.2020.101560] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/07/2020] [Accepted: 09/14/2020] [Indexed: 12/16/2022]
Abstract
The gopher tortoise tick, Amblyomma tuberculatum, is known to parasitize keystone ectotherm reptile species. The biological success of ticks requires precise mechanisms to evade host hemostatic and immune responses. Acquisition of a full blood meal requires attachment, establishment of the blood pool, and engorgement of the tick. Tick saliva contains molecules which counter the host responses to allow uninterrupted feeding on the host. RNASeq of the salivary glands of Amblyomma tuberculatum ticks were sequenced resulting in 138,030 pyrosequencing reads which were assembled into 29,991 contigs. A total of 1875 coding sequences were deduced from the transcriptome assembly, including 602 putative secretory and 982 putative housekeeping proteins. The annotated data sets are available as a hyperlinked spreadsheet. The sialotranscriptome assembled for this tick species made available a valuable resource for mining novel pharmacological activities and comparative analysis.
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Affiliation(s)
- Shahid Karim
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - Deepak Kumar
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - Steve Adamson
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - Joshua R Ennen
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - Carl P Qualls
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - José M C Ribeiro
- Vector Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12732 Twinbrook Parkway, Room 3E28, Rockville MD 20852, USA.
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12
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Hia YL, Tan KY, Tan CH. Comparative venom proteomics of banded krait (Bungarus fasciatus) from five geographical locales: Correlation of venom lethality, immunoreactivity and antivenom neutralization. Acta Trop 2020; 207:105460. [PMID: 32278639 DOI: 10.1016/j.actatropica.2020.105460] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 03/25/2020] [Indexed: 10/24/2022]
Abstract
The banded krait, Bungarus fasciatus is a medically important venomous snake in Asia. The wide distribution of this species in Southeast Asia and southern China indicates potential geographical variation of the venom which may impact the clinical management of snakebite envenomation. This study investigated the intraspecific venom variation of B. fasciatus from five geographical locales through a venom decomplexing proteomic approach, followed by toxinological and immunological studies. The venom proteomes composed of a total of 9 toxin families, comprising 22 to 31 proteoforms at varying abundances. The predominant proteins were phospholipase A2 (including beta-bungarotoxin), Kunitz-type serine protease inhibitor (KSPI) and three-finger toxins (3FTx), which are toxins that cause neurotoxicity and lethality. The venom lethality varied with geographical origins of the snake, with intravenous median lethal doses (LD50) ranging from 0.45-2.55 µg/g in mice. The Thai Bungarus fasciatus monovalent antivenom (BFMAV) demonstrated a dose-dependent increasing immunological binding activity toward all venoms; however, its in vivo neutralization efficacy varied vastly with normalized potency values ranging from 3 to 28 mg/g, presumably due to the compositional differences of dominant proteins in the different venoms. The findings support that antivenom use should be optimized in different geographical areas. The development of a pan-regional antivenom may be a more sustainable solution for the treatment of snakebite envenomation.
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13
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Modahl CM, Brahma RK, Koh CY, Shioi N, Kini RM. Omics Technologies for Profiling Toxin Diversity and Evolution in Snake Venom: Impacts on the Discovery of Therapeutic and Diagnostic Agents. Annu Rev Anim Biosci 2019; 8:91-116. [PMID: 31702940 DOI: 10.1146/annurev-animal-021419-083626] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Snake venoms are primarily composed of proteins and peptides, and these toxins have developed high selectivity to their biological targets. This makes venoms interesting for exploration into protein evolution and structure-function relationships. A single venom protein superfamily can exhibit a variety of pharmacological effects; these variations in activity originate from differences in functional sites, domains, posttranslational modifications, and the formations of toxin complexes. In this review, we discuss examples of how the major venom protein superfamilies have diversified, as well as how newer technologies in the omics fields, such as genomics, transcriptomics, and proteomics, can be used to characterize both known and unknown toxins.Because toxins are bioactive molecules with a rich diversity of activities, they can be useful as therapeutic and diagnostic agents, and successful examples of toxin applications in these areas are also reviewed. With the current rapid pace of technology, snake venom research and its applications will only continue to expand.
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Affiliation(s)
- Cassandra M Modahl
- Protein Science Lab, Department of Biological Sciences, University of Singapore, Singapore 119077; , ,
| | - Rajeev Kungur Brahma
- Protein Science Lab, Department of Biological Sciences, University of Singapore, Singapore 119077; , ,
| | - Cho Yeow Koh
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077;
| | - Narumi Shioi
- Protein Science Lab, Department of Biological Sciences, University of Singapore, Singapore 119077; , , .,Department of Chemistry, Faculty of Science, Fukuoka University, Fukuoka 814-0180, Japan;
| | - R Manjunatha Kini
- Protein Science Lab, Department of Biological Sciences, University of Singapore, Singapore 119077; , ,
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14
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Williams HF, Layfield HJ, Vallance T, Patel K, Bicknell AB, Trim SA, Vaiyapuri S. The Urgent Need to Develop Novel Strategies for the Diagnosis and Treatment of Snakebites. Toxins (Basel) 2019; 11:E363. [PMID: 31226842 PMCID: PMC6628419 DOI: 10.3390/toxins11060363] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 06/18/2019] [Accepted: 06/18/2019] [Indexed: 01/09/2023] Open
Abstract
Snakebite envenoming (SBE) is a priority neglected tropical disease, which kills in excess of 100,000 people per year. Additionally, many millions of survivors also suffer through disabilities and long-term health consequences. The only treatment for SBE, antivenom, has a number of major associated problems, not least, adverse reactions and limited availability. This emphasises the necessity for urgent improvements to the management of this disease. Administration of antivenom is too frequently based on symptomatology, which results in wasting crucial time. The majority of SBE-affected regions rely on broad-spectrum polyvalent antivenoms that have a low content of case-specific efficacious immunoglobulins. Research into small molecular therapeutics such as varespladib/methyl-varespladib (PLA2 inhibitors) and batimastat/marimastat (metalloprotease inhibitors) suggest that such adjunctive treatments could be hugely beneficial to victims. Progress into toxin-specific monoclonal antibodies as well as alternative binding scaffolds such as aptamers hold much promise for future treatment strategies. SBE is not implicit during snakebite, due to venom metering. Thus, the delay between bite and symptom presentation is critical and when symptoms appear it may often already be too late to effectively treat SBE. The development of reliable diagnostical tools could therefore initiate a paradigm shift in the treatment of SBE. While the complete eradication of SBE is an impossibility, mitigation is in the pipeline, with new treatments and diagnostics rapidly emerging. Here we critically review the urgent necessity for the development of diagnostic tools and improved therapeutics to mitigate the deaths and disabilities caused by SBE.
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Affiliation(s)
| | | | - Thomas Vallance
- School of Pharmacy, University of Reading, Reading RG6 6AH, UK.
| | - Ketan Patel
- School of Biological Sciences, University of Reading, Reading RG6 6AH, UK.
| | - Andrew B Bicknell
- School of Biological Sciences, University of Reading, Reading RG6 6AH, UK.
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15
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Möller C, Davis WC, Clark E, DeCaprio A, Marí F. Conodipine-P1-3, the First Phospholipases A 2 Characterized from Injected Cone Snail Venom. Mol Cell Proteomics 2019; 18:876-891. [PMID: 30765458 DOI: 10.1074/mcp.ra118.000972] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 02/06/2019] [Indexed: 12/30/2022] Open
Abstract
The phospholipase A2 (PLA2s) superfamily are ubiquitous small enzymes that catalyze the hydrolysis of phospholipids at the sn-2 ester bond. PLA2s in the venom of cone snails (conodipines, Cdpi) are composed of two chains termed as alpha and beta subunits. Conodipines are categorized within the group IX of PLA2s. Here we describe the purification and biochemical characterization of three conodipines (Cdpi-P1, -P2 and -P3) isolated from the injected venom of Conus purpurascens Using proteomics methods, we determined the full sequences of all three conodipines. Conodipine-P1-3 have conserved consensus catalytic domain residues, including the Asp/His dyad. Additionally, these enzymes are expressed as a mixture of proline hydroxylated isoforms. The activities of the native Conodipine-Ps were evaluated by conventional colorimetric and by MS-based methods, which provide the first detailed cone snail venom conodipine activity monitored by mass spectrometry. Conodipines can have medicinal applications such inhibition of cancer proliferation, bacterial and viral infections among others.
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Affiliation(s)
- Carolina Möller
- From the ‡Marine Biochemical Sciences, Chemical Sciences Division, National Institute of Standards and Technology, 331 Fort Johnson Road, Charleston, South Carolina, 29412
| | - W Clay Davis
- From the ‡Marine Biochemical Sciences, Chemical Sciences Division, National Institute of Standards and Technology, 331 Fort Johnson Road, Charleston, South Carolina, 29412
| | - Evan Clark
- §Department of Biomedical Sciences, Florida Atlantic University, Boca Raton, Florida, 33431
| | - Anthony DeCaprio
- ¶Department of Chemistry and Biochemistry, Florida International University, SW 8th St, Miami, Florida, 33119
| | - Frank Marí
- From the ‡Marine Biochemical Sciences, Chemical Sciences Division, National Institute of Standards and Technology, 331 Fort Johnson Road, Charleston, South Carolina, 29412;.
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16
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Neurobiology and therapeutic applications of neurotoxins targeting transmitter release. Pharmacol Ther 2019; 193:135-155. [DOI: 10.1016/j.pharmthera.2018.08.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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17
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Kaur S, Devi A, Saikia B, Doley R. Expression and characterization of Flavikunin: A Kunitz-type serine protease inhibitor identified in the venom gland cDNA library of Bungarus flaviceps. J Biochem Mol Toxicol 2018; 33:e22273. [PMID: 30536558 DOI: 10.1002/jbt.22273] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 10/13/2018] [Accepted: 10/26/2018] [Indexed: 01/02/2023]
Abstract
Trancriptomic analysis of the venom gland cDNA library of Bungarus flaviceps revealed Kunitz-type serine protease inhibitor as one of the major venom protein families with three groups A, B, C. One of the group B isoforms named Flavikunin, which lacked an extra cysteine residue involved in disulfide bond formation in β-bungarotoxin, was synthesized, cloned, and overexpressed in Escherichia coli. To decipher the structure-function relationship, the P1 residue of Flavikunin, histidine, was mutated to alanine and arginine. Purified wild-type and mutant Flavikunins were screened against serine proteases-thrombin, factor Xa, trypsin, chymotrypsin, plasmin, and elastase. The wild-type and mutant Flavikunin (H∆R) inhibited plasmin with an IC 50 of 0.48 and 0.35 µM, respectively. The in-silico study showed that P1 residue of wild-type and mutant (H∆R) Flavikunin interacted with S1' and S1 site of plasmin, respectively. Thus, histidine at the P1 position was found to be involved in plasmin inhibition with mild anticoagulant activity.
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Affiliation(s)
- Simran Kaur
- Molecular Toxinology Lab, Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, India
| | - Arpita Devi
- Molecular Toxinology Lab, Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, India
| | - Bhaskarjyoti Saikia
- Molecular Toxinology Lab, Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, India
| | - Robin Doley
- Molecular Toxinology Lab, Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, India
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18
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Engineered nanoparticles bind elapid snake venom toxins and inhibit venom-induced dermonecrosis. PLoS Negl Trop Dis 2018; 12:e0006736. [PMID: 30286075 PMCID: PMC6171825 DOI: 10.1371/journal.pntd.0006736] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 08/07/2018] [Indexed: 11/19/2022] Open
Abstract
Envenomings by snakebites constitute a serious and challenging global health issue. The mainstay in the therapy of snakebite envenomings is the parenteral administration of animal-derived antivenoms. Significantly, antivenoms are only partially effective in the control of local tissue damage. A novel approach to mitigate the progression of local tissue damage that could complement the antivenom therapy of envenomings is proposed. We describe an abiotic hydrogel nanoparticle engineered to bind to and modulate the activity of a diverse array of PLA2 and 3FTX isoforms found in Elapidae snake venoms. These two families of protein toxins share features that are associated with their common (membrane) targets, allowing for nanoparticle sequestration by a mechanism that differs from immunological (epitope) selection. The nanoparticles are non-toxic in mice and inhibit dose-dependently the dermonecrotic activity of Naja nigricollis venom.
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19
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Estevão-Costa MI, Sanz-Soler R, Johanningmeier B, Eble JA. Snake venom components in medicine: From the symbolic rod of Asclepius to tangible medical research and application. Int J Biochem Cell Biol 2018; 104:94-113. [PMID: 30261311 DOI: 10.1016/j.biocel.2018.09.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/03/2018] [Accepted: 09/19/2018] [Indexed: 12/21/2022]
Abstract
Both mythologically and logically, snakes have always fascinated man. Snakes have attracted both awe and fear not only because of the elegant movement of their limbless bodies, but also because of the potency of their deadly venoms. Practically, in 2017, the world health organization (WHO) listed snake envenomation as a high priority neglected disease, as snakes inflict up to 2.7 million poisonous bites, around 100.000 casualties, and about three times as many invalidities on man. The venoms of poisonous snakes are a cocktail of potent compounds which specifically and avidly target numerous essential molecules with high efficacy. The individual effects of all venom toxins integrate into lethal dysfunctions of almost any organ system. It is this efficacy and specificity of each venom component, which after analysis of its structure and activity may serve as a potential lead structure for chemical imitation. Such toxin mimetics may help in influencing a specific body function pharmaceutically for the sake of man's health. In this review article, we will give some examples of snake venom components which have spurred the development of novel pharmaceutical compounds. Moreover, we will provide examples where such snake toxin-derived mimetics are in clinical use, trials, or consideration for further pharmaceutical exploitation, especially in the fields of hemostasis, thrombosis, coagulation, and metastasis. Thus, it becomes clear why a snake captured its symbolic place at the Asclepius rod with good reason still nowadays.
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Affiliation(s)
- Maria-Inacia Estevão-Costa
- Institute of Physiological Chemistry and Pathobiochemistry, University of Münster, Waldeyerstr. 15, 48149, Münster, Germany
| | - Raquel Sanz-Soler
- Institute of Physiological Chemistry and Pathobiochemistry, University of Münster, Waldeyerstr. 15, 48149, Münster, Germany
| | - Benjamin Johanningmeier
- Institute of Physiological Chemistry and Pathobiochemistry, University of Münster, Waldeyerstr. 15, 48149, Münster, Germany
| | - Johannes A Eble
- Institute of Physiological Chemistry and Pathobiochemistry, University of Münster, Waldeyerstr. 15, 48149, Münster, Germany.
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20
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Correnti CE, Gewe MM, Mehlin C, Bandaranayake AD, Johnsen WA, Rupert PB, Brusniak MY, Clarke M, Burke SE, De Van Der Schueren W, Pilat K, Turnbaugh SM, May D, Watson A, Chan MK, Bahl CD, Olson JM, Strong RK. Screening, large-scale production and structure-based classification of cystine-dense peptides. Nat Struct Mol Biol 2018; 25:270-278. [PMID: 29483648 PMCID: PMC5840021 DOI: 10.1038/s41594-018-0033-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 01/23/2018] [Indexed: 12/04/2022]
Abstract
Peptides folded through interwoven disulfides display extreme biochemical properties and unique medicinal potential. However, their exploitation has been hampered by the limited amounts isolatable from natural sources and the expense of chemical synthesis. We developed reliable biological methods for high-throughput expression, screening and large-scale production of these peptides: 46 were successfully produced in multimilligram quantities, and >600 more were deemed expressible through stringent screening criteria. Many showed extreme resistance to temperature, proteolysis and/or reduction, and all displayed inhibitory activity against at least 1 of 20 ion channels tested, thus confirming their biological functionality. Crystal structures of 12 confirmed proper cystine topology and the utility of crystallography to study these molecules but also highlighted the need for rational classification. Previous categorization attempts have focused on limited subsets featuring distinct motifs. Here we present a global definition, classification and analysis of >700 structures of cystine-dense peptides, providing a unifying framework for these molecules.
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Affiliation(s)
- Colin E Correnti
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Mesfin M Gewe
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Christopher Mehlin
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Ashok D Bandaranayake
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - William A Johnsen
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Peter B Rupert
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Mi-Youn Brusniak
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Midori Clarke
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Skyler E Burke
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | | | - Kristina Pilat
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Shanon M Turnbaugh
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Damon May
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Alex Watson
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Man Kid Chan
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | | | - James M Olson
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
| | - Roland K Strong
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
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21
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Elucidating the biogeographical variation of the venom of Naja naja (spectacled cobra) from Pakistan through a venom-decomplexing proteomic study. J Proteomics 2018; 175:156-173. [DOI: 10.1016/j.jprot.2017.12.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Revised: 11/30/2017] [Accepted: 12/18/2017] [Indexed: 02/08/2023]
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22
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Vulfius CA, Kasheverov IE, Kryukova EV, Spirova EN, Shelukhina IV, Starkov VG, Andreeva TV, Faure G, Zouridakis M, Tsetlin VI, Utkin YN. Pancreatic and snake venom presynaptically active phospholipases A2 inhibit nicotinic acetylcholine receptors. PLoS One 2017; 12:e0186206. [PMID: 29023569 PMCID: PMC5638340 DOI: 10.1371/journal.pone.0186206] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 09/27/2017] [Indexed: 01/08/2023] Open
Abstract
Phospholipases A2 (PLA2s) are enzymes found throughout the animal kingdom. They hydrolyze phospholipids in the sn-2 position producing lysophospholipids and unsaturated fatty acids, agents that can damage membranes. PLA2s from snake venoms have numerous toxic effects, not all of which can be explained by phospholipid hydrolysis, and each enzyme has a specific effect. We have earlier demonstrated the capability of several snake venom PLA2s with different enzymatic, cytotoxic, anticoagulant and antiproliferative properties, to decrease acetylcholine-induced currents in Lymnaea stagnalis neurons, and to compete with α-bungarotoxin for binding to nicotinic acetylcholine receptors (nAChRs) and acetylcholine binding protein. Since nAChRs are implicated in postsynaptic and presynaptic activities, in this work we probe those PLA2s known to have strong presynaptic effects, namely β-bungarotoxin from Bungarus multicinctus and crotoxin from Crotalus durissus terrificus. We also wished to explore whether mammalian PLA2s interact with nAChRs, and have examined non-toxic PLA2 from porcine pancreas. It was found that porcine pancreatic PLA2 and presynaptic β-bungarotoxin blocked currents mediated by nAChRs in Lymnaea neurons with IC50s of 2.5 and 4.8 μM, respectively. Crotoxin competed with radioactive α-bungarotoxin for binding to Torpedo and human α7 nAChRs and to the acetylcholine binding protein. Pancreatic PLA2 interacted similarly with these targets; moreover, it inhibited radioactive α-bungarotoxin binding to the water-soluble extracellular domain of human α9 nAChR, and blocked acetylcholine induced currents in human α9α10 nAChRs heterologously expressed in Xenopus oocytes. These and our earlier results show that all snake PLA2s, including presynaptically active crotoxin and β-bungarotoxin, as well as mammalian pancreatic PLA2, interact with nAChRs. The data obtained suggest that this interaction may be a general property of all PLA2s, which should be proved by further experiments.
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Affiliation(s)
- Catherine A. Vulfius
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Igor E. Kasheverov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Elena V. Kryukova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Ekaterina N. Spirova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Irina V. Shelukhina
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Vladislav G. Starkov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Tatyana V. Andreeva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Grazyna Faure
- Unité Récepteurs-Canaux, Institut Pasteur, Paris, France
| | | | - Victor I. Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Yuri N. Utkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
- * E-mail:
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23
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Župunski V, Kordiš D. Strong and widespread action of site-specific positive selection in the snake venom Kunitz/BPTI protein family. Sci Rep 2016; 6:37054. [PMID: 27841308 PMCID: PMC5107962 DOI: 10.1038/srep37054] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 10/24/2016] [Indexed: 12/22/2022] Open
Abstract
S1 family of serine peptidases is the largest family of peptidases. They are specifically inhibited by the Kunitz/BPTI inhibitors. Kunitz domain is characterized by the compact 3D structure with the most important inhibitory loops for the inhibition of S1 peptidases. In the present study we analysed the action of site-specific positive selection and its impact on the structurally and functionally important parts of the snake venom Kunitz/BPTI family of proteins. By using numerous models we demonstrated the presence of large numbers of site-specific positively selected sites that can reach between 30-50% of the Kunitz domain. The mapping of the positively selected sites on the 3D model of Kunitz/BPTI inhibitors has shown that these sites are located in the inhibitory loops 1 and 2, but also in the Kunitz scaffold. Amino acid replacements have been found exclusively on the surface, and the vast majority of replacements are causing the change of the charge. The consequence of these replacements is the change in the electrostatic potential on the surface of the Kunitz/BPTI proteins that may play an important role in the precise targeting of these inhibitors into the active site of S1 family of serine peptidases.
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Affiliation(s)
- Vera Župunski
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Dušan Kordiš
- Department of Molecular and Biomedical Sciences, Josef Stefan Institute, Ljubljana, Slovenia
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24
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Reeks TA, Fry BG, Alewood PF. Privileged frameworks from snake venom. Cell Mol Life Sci 2015; 72:1939-58. [PMID: 25693678 PMCID: PMC11113608 DOI: 10.1007/s00018-015-1844-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 01/22/2015] [Accepted: 01/26/2015] [Indexed: 11/25/2022]
Abstract
Venom as a form of chemical prey capture is a key innovation that has underpinned the explosive radiation of the advanced snakes (Caenophidia). Small venom proteins are often rich in disulfide bonds thus facilitating stable molecular scaffolds that present key functional residues on the protein surface. New toxin types are initially developed through the venom gland over-expression of normal body proteins, their subsequent gene duplication and diversification that leads to neofunctionalisation as random mutations modify their structure and function. This process has led to preferentially selected (privileged) cysteine-rich scaffolds that enable the snake to build arrays of toxins many of which may lead to therapeutic products and research tools. This review focuses on cysteine-rich small proteins and peptides found in snake venoms spanning natriuretic peptides to phospholipase enzymes, while highlighting their three-dimensional structures and biological functions as well as their potential as therapeutic agents or research tools.
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Affiliation(s)
- T. A. Reeks
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072 Australia
| | - B. G. Fry
- Venom Evolution Lab, School of Biological Sciences, The University of Queensland, St Lucia, QLD 4072 Australia
| | - P. F. Alewood
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072 Australia
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25
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Hargreaves AD, Swain MT, Logan DW, Mulley JF. Testing the Toxicofera: comparative transcriptomics casts doubt on the single, early evolution of the reptile venom system. Toxicon 2014; 92:140-56. [PMID: 25449103 DOI: 10.1016/j.toxicon.2014.10.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 10/01/2014] [Indexed: 12/01/2022]
Abstract
The identification of apparently conserved gene complements in the venom and salivary glands of a diverse set of reptiles led to the development of the Toxicofera hypothesis - the single, early evolution of the venom system in reptiles. However, this hypothesis is based largely on relatively small scale EST-based studies of only venom or salivary glands and toxic effects have been assigned to only some putative Toxicoferan toxins in some species. We set out to examine the distribution of these proposed venom toxin transcripts in order to investigate to what extent conservation of gene complements may reflect a bias in previous sampling efforts. Our quantitative transcriptomic analyses of venom and salivary glands and other body tissues in five species of reptile, together with the use of available RNA-Seq datasets for additional species, shows that the majority of genes used to support the establishment and expansion of the Toxicofera are in fact expressed in multiple body tissues and most likely represent general maintenance or "housekeeping" genes. The apparent conservation of gene complements across the Toxicofera therefore reflects an artefact of incomplete tissue sampling. We therefore conclude that venom has evolved multiple times in reptiles.
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Affiliation(s)
- Adam D Hargreaves
- School of Biological Sciences, Bangor University, Brambell Building, Deiniol Road, Bangor, Gwynedd LL57 2UW, United Kingdom.
| | - Martin T Swain
- Institute of Biological, Environmental & Rural Sciences, Aberystwyth University, Penglais, Aberystwyth, Ceredigion SY23 3DA, United Kingdom.
| | - Darren W Logan
- Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1HH, United Kingdom.
| | - John F Mulley
- School of Biological Sciences, Bangor University, Brambell Building, Deiniol Road, Bangor, Gwynedd LL57 2UW, United Kingdom.
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Roly ZY, Hasan SMN, Ferdaus KMKB, Reza MA. Predicted structure model of Bungarotoxin from Bungarus fasciatus snake. Bioinformation 2014; 10:617-22. [PMID: 25489170 PMCID: PMC4248343 DOI: 10.6026/97320630010617] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 09/20/2014] [Indexed: 11/23/2022] Open
Abstract
Snake venoms are cocktails comprising combinations of different proteins, peptides, enzymes and toxins. Snake toxins have diverse characteristics having different molecular configuration, structure and mode of action. Many toxins derived from snake venom have distinct pharmacological activities. Venom from Bungarus fasciatus (commonly known as banded krait) is a species of elapid snake found on the South East Asia and Indian sub-continent, mainly contains neurotoxins. Beta bungartotoxin is the major fraction of Bungarus venom and particularly act pre-synaptically by obstructing neurotransmitter release. This toxin in other snake species functionally forms a heterodimer containing two different subunits (A and B). Dimerization of these two chains is a pre-requisite for the proper functionality of this protein. However, B. fasciatus bungartotoxin contains only B chain and their structural orientation in yet to be resolved. Therefore, it is of interest to describe the predicted structure model of the toxin for functional insights. In this work we analyzed the neurotoxic nature, their alignments, secondary and three dimensional structures, functions, active sites and stability with the help of different bioinformatical tools. A comprehensive analysis of the predicted model provides approaching to the functional interpretation of its molecular action.
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Affiliation(s)
- Zahida Yesmin Roly
- Department of Genetic Engineering and Biotechnology, Faculty of Life and Earth Science, University of Rajshahi, Rajshahi-6205,Bangladesh
- Authors equally contributed
| | - SM Naimul Hasan
- Department of Genetic Engineering and Biotechnology, Faculty of Life and Earth Science, University of Rajshahi, Rajshahi-6205,Bangladesh
- Authors equally contributed
| | - KMKB Ferdaus
- Assistant Professor, Department of Genetic Engineering and Biotechnology, University of Rajshahi, Rajshahi -6205,Bangladesh
| | - Md Abu Reza
- Professor, Department of Genetic Engineering and Biotechnology, University of Rajshahi, Rajshahi-6205, Bangladesh
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Ye F, Zheng Y, Wang X, Tan X, Zhang T, Xin W, Wang J, Huang Y, Fan Q, Wang J. Recognition of Bungarus multicinctus venom by a DNA aptamer against β-bungarotoxin. PLoS One 2014; 9:e105404. [PMID: 25144237 PMCID: PMC4140777 DOI: 10.1371/journal.pone.0105404] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 07/21/2014] [Indexed: 01/03/2023] Open
Abstract
Antibody-based technology is the main method for diagnosis and treatment of snake bite envenoming currently. However, the development of an antibody, polyclonal or monoclonal, is a complicated and costly procedure. Aptamers are single stranded oligonucleotides that recognize specific targets such as proteins and have shown great potential over the years as diagnostic and therapeutic agents. In contrast to antibodies, aptamers can be selected in vitro without immunization of animals, and synthesized chemically with extreme accuracy, low cost and high degree of purity. In this study we firstly report on the identification of DNA aptamers that bind to β-bungarotoxin (β-BuTx), a neurotoxin from the venom of Bungarus multicinctus. A plate-SELEX method was used for the selection of β-BuTx specific aptamers. After 10 rounds of selection, four aptamer candidates were obtained, with the dissociation constant ranged from 65.9 nM to 995 nM measured by fluorescence spectroscopy. Competitive binding assays using both the fluorescently labeled and unlabeled aptamers revealed that the four aptamers bound to the same binding site of β-BuTx. The best binder, βB-1, bound specifically to β-BuTx, but not to BSA, casein or α-Bungarotoxin. Moreover, electrophoretic mobility shift assay and enzyme-linked aptamer assay demonstrated that βB-1 could discriminate B. multicinctus venom from other snake venoms tested. The results suggest that aptamer βB-1 can serve as a useful tool for the design and development of drugs and diagnostic tests for β-BuTx poisoning and B. multicinctus bites.
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Affiliation(s)
- Fengping Ye
- State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
- Institute of Military Medicine, Chengdu Military Region's Center for Disease Control & Prevention, Kunming, China
| | - Ying Zheng
- Institute of Military Medicine, Chengdu Military Region's Center for Disease Control & Prevention, Kunming, China
| | - Xi Wang
- Institute of Military Medicine, Chengdu Military Region's Center for Disease Control & Prevention, Kunming, China
| | - Xiaolong Tan
- Institute of Military Medicine, Chengdu Military Region's Center for Disease Control & Prevention, Kunming, China
| | - Tao Zhang
- State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Wenwen Xin
- State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Jie Wang
- Institute of Military Medicine, Chengdu Military Region's Center for Disease Control & Prevention, Kunming, China
| | - Yong Huang
- Institute of Military Medicine, Chengdu Military Region's Center for Disease Control & Prevention, Kunming, China
| | - Quanshui Fan
- Institute of Military Medicine, Chengdu Military Region's Center for Disease Control & Prevention, Kunming, China
| | - Jinglin Wang
- State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
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Baconguis I, Bohlen CJ, Goehring A, Julius D, Gouaux E. X-ray structure of acid-sensing ion channel 1-snake toxin complex reveals open state of a Na(+)-selective channel. Cell 2014; 156:717-29. [PMID: 24507937 DOI: 10.1016/j.cell.2014.01.011] [Citation(s) in RCA: 221] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 11/20/2013] [Accepted: 01/07/2014] [Indexed: 12/25/2022]
Abstract
Acid-sensing ion channels (ASICs) detect extracellular protons produced during inflammation or ischemic injury and belong to the superfamily of degenerin/epithelial sodium channels. Here, we determine the cocrystal structure of chicken ASIC1a with MitTx, a pain-inducing toxin from the Texas coral snake, to define the structure of the open state of ASIC1a. In the MitTx-bound open state and in the previously determined low-pH desensitized state, TM2 is a discontinuous α helix in which the Gly-Ala-Ser selectivity filter adopts an extended, belt-like conformation, swapping the cytoplasmic one-third of TM2 with an adjacent subunit. Gly 443 residues of the selectivity filter provide a ring of three carbonyl oxygen atoms with a radius of ∼3.6 Å, presenting an energetic barrier for hydrated ions. The ASIC1a-MitTx complex illuminates the mechanism of MitTx action, defines the structure of the selectivity filter of voltage-independent, sodium-selective ion channels, and captures the open state of an ASIC.
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Affiliation(s)
- Isabelle Baconguis
- Vollum Institute, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - Christopher J Bohlen
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - April Goehring
- Vollum Institute, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - David Julius
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Eric Gouaux
- Vollum Institute, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA; Howard Hughes Medical Institute, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
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Understanding the evolutionary structural variability and target specificity of tick salivary Kunitz peptides using next generation transcriptome data. BMC Evol Biol 2014; 14:4. [PMID: 24397261 PMCID: PMC3890586 DOI: 10.1186/1471-2148-14-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 12/13/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ticks are blood-sucking arthropods and a primary function of tick salivary proteins is to counteract the host's immune response. Tick salivary Kunitz-domain proteins perform multiple functions within the feeding lesion and have been classified as venoms; thereby, constituting them as one of the important elements in the arms race with the host. The two main mechanisms advocated to explain the functional heterogeneity of tick salivary Kunitz-domain proteins are gene sharing and gene duplication. Both do not, however, elucidate the evolution of the Kunitz family in ticks from a structural dynamic point of view. The Red Queen hypothesis offers a fruitful theoretical framework to give a dynamic explanation for host-parasite interactions. Using the recent salivary gland Ixodes ricinus transcriptome we analyze, for the first time, single Kunitz-domain encoding transcripts by means of computational, structural bioinformatics and phylogenetic approaches to improve our understanding of the structural evolution of this important multigenic protein family. RESULTS Organizing the I. ricinus single Kunitz-domain peptides based on their cysteine motif allowed us to specify a putative target and to relate this target specificity to Illumina transcript reads during tick feeding. We observe that several of these Kunitz peptide groups vary in their translated amino acid sequence, secondary structure, antigenicity, and intrinsic disorder, and that the majority of these groups are subject to a purifying (negative) selection. We finalize by describing the evolution and emergence of these Kunitz peptides. The overall interpretation of our analyses discloses a rapidly emerging Kunitz group with a distinct disulfide bond pattern from the I. ricinus salivary gland transcriptome. CONCLUSIONS We propose a model to explain the structural and functional evolution of tick salivary Kunitz peptides that we call target-oriented evolution. Our study reveals that combining analytical approaches (transcriptomes, computational, bioinformatics and phylogenetics) improves our understanding of the biological functions of important salivary gland mediators during tick feeding.
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Yang W, Feng J, Wang B, Cao Z, Li W, Wu Y, Chen Z. BF9, the first functionally characterized snake toxin peptide with Kunitz-type protease and potassium channel inhibiting properties. J Biochem Mol Toxicol 2013; 28:76-83. [PMID: 24243656 DOI: 10.1002/jbt.21538] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Revised: 10/16/2013] [Indexed: 12/14/2022]
Abstract
Although numerous Kunitz-type toxins were isolated from snake venom, no bifunctional Kunitz-type snake toxins with protease and potassium channel inhibiting properties have been reported till now. With the help of bioinformatics analyses and biological experiments, we characterized Kunitz-type snake toxin BF9 as a bifunctional peptide. Enzyme and inhibitor reaction kinetics experiments showed that BF9 inhibited α-chymotrypsin with Ki value of 1.8 × 10⁻⁸ M. Electrophysiological experiments showed that BF9 inhibited the Kv1.3 potassium channel with an IC₅₀ of 120.0 nM, which demonstrated that serine protease inhibitor BF9 could also inhibit potassium channels. In addition, the key amino acids of BF9 responsible for the unique bifunctional mechanism are further investigated. To the best of our knowledge, BF9 is the first Kunitz-type snake peptide with the unique bifunctionality of potassium channel and serine protease inhibiting properties, providing novel insights into divergent evolution and functional applications of snake Kunitz-type peptides.
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Affiliation(s)
- Weishan Yang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, People's Republic of China
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Incamnoi P, Patramanon R, Thammasirirak S, Chaveerach A, Uawonggul N, Sukprasert S, Rungsa P, Daduang J, Daduang S. Heteromtoxin (HmTx), a novel heterodimeric phospholipase A2 from Heterometrus laoticus scorpion venom. Toxicon 2013; 61:62-71. [DOI: 10.1016/j.toxicon.2012.10.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 09/22/2012] [Accepted: 10/23/2012] [Indexed: 10/27/2022]
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Abstract
Cnidaria is a rich phylum that includes thousands of marine species. In this study, we focused on Anthozoa and Hydrozoa that are represented by the Nematostella vectensis (Sea anemone) and Hydra magnipapillata genomes. We present a method for ranking the toxin-like candidates from complete proteomes of Cnidaria. Toxin-like functions were revealed using ClanTox, a statistical machine-learning predictor trained on ion channel inhibitors from venomous animals. Fundamental features that were emphasized in training ClanTox include cysteines and their spacing along the sequences. Among the 83,000 proteins derived from Cnidaria representatives, we found 170 candidates that fulfill the properties of toxin-like-proteins, the vast majority of which were previously unrecognized as toxins. An additional 394 short proteins exhibit characteristics of toxin-like proteins at a moderate degree of confidence. Remarkably, only 11% of the predicted toxin-like proteins were previously classified as toxins. Based on our prediction methodology and manual annotation, we inferred functions for over 400 of these proteins. Such functions include protease inhibitors, membrane pore formation, ion channel blockers and metal binding proteins. Many of the proteins belong to small families of paralogs. We conclude that the evolutionary expansion of toxin-like proteins in Cnidaria contributes to their fitness in the complex environment of the aquatic ecosystem.
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Affiliation(s)
- Yitshak Tirosh
- Department of Biological Chemistry, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; (Y.T.); (M.A.)
| | - Itai Linial
- The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
| | - Manor Askenazi
- Department of Biological Chemistry, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; (Y.T.); (M.A.)
| | - Michal Linial
- Department of Biological Chemistry, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; (Y.T.); (M.A.)
- Author to whom correspondence should be addressed; ; Tel.: +972-2-658-5425; Fax: +972-2-658-6448
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Wen YL, Wu BJ, Kao PH, Fu YS, Chang LS. Antibacterial and membrane-damaging activities of β
-bungarotoxin B chain. J Pept Sci 2012; 19:1-8. [DOI: 10.1002/psc.2463] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 09/29/2012] [Accepted: 10/07/2012] [Indexed: 12/31/2022]
Affiliation(s)
- Yi-Lin Wen
- Institute of Biomedical Sciences; National Sun Yat-Sen University; Kaohsiung 804 Taiwan
| | - Bao-Jueng Wu
- Department of Internal Medicine; Zuoying Armed Forces General Hospital; Kaohsiung 813 Taiwan
| | - Pei-Hsiu Kao
- Institute of Biomedical Sciences; National Sun Yat-Sen University; Kaohsiung 804 Taiwan
| | - Yaw-Syan Fu
- Department of Biomedical Science and Environmental Biology; Kaohsiung Medical University; Kaohsiung 807 Taiwan
| | - Long-Sen Chang
- Institute of Biomedical Sciences; National Sun Yat-Sen University; Kaohsiung 804 Taiwan
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Cendron L, Mičetić I, Polverino de Laureto P, Paoli M. Structural analysis of trimeric phospholipase A2 neurotoxin from the Australian taipan snake venom. FEBS J 2012; 279:3121-35. [PMID: 22776098 DOI: 10.1111/j.1742-4658.2012.08691.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Snake pre-synaptic neurotoxins endowed with phospholipase A(2) activity are potent inducers of paralysis through the specific disruption of the neuromuscular junction pre-synaptic membrane and represent a valuable tool for investigating neuronal degeneration and recovery. They have different structural complexity and a wide range of lethal potency and enzymatic activity, although they share a similar mechanism of action. Although no correlation has been reported between neurotoxicity and enzymatic activity, toxicity increases with structural complexity and phospholipase A(2) oligomers show 10-fold lower LD(50) values compared to their monomeric counterparts. To date, no structural study has been performed on multimeric SPANs with the aim of shedding light on the correlation between structural complexity and neurotoxicity. In the present study, we investigated the structure of taipoxin, a trimeric phospholipase A(2) neurotoxin, as well as that of its subunits, by X-ray crystallography and small angle X-ray scattering analysis. We present the high-resolution structure of two isoforms of the taipoxin β subunit, which show no neurotoxic activity but enhance the activity of the other subunits in the complex. One isoform shows no structural change that could justify the lack of activity. The other displays three point mutations in critical positions for the catalytic activity. Moreover, we designed a model for the quaternary structure of taipoxin under physiological conditions, in which the three subunits are organized into a flat holotoxin with the substrate binding sockets exposed on the same side of the complex, which suggests a role for this interface in the toxin-membrane interaction.
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Affiliation(s)
- Laura Cendron
- Department of Biological Chemistry, University of Padova, Italy
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A deep insight into the sialotranscriptome of the gulf coast tick, Amblyomma maculatum. PLoS One 2011; 6:e28525. [PMID: 22216098 PMCID: PMC3244413 DOI: 10.1371/journal.pone.0028525] [Citation(s) in RCA: 156] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 11/09/2011] [Indexed: 01/10/2023] Open
Abstract
Background Saliva of blood sucking arthropods contains compounds that antagonize their hosts' hemostasis, which include platelet aggregation, vasoconstriction and blood clotting; saliva of these organisms also has anti-inflammatory and immunomodullatory properties. Perhaps because hosts mount an active immune response against these compounds, the diversity of these compounds is large even among related blood sucking species. Because of these properties, saliva helps blood feeding as well as help the establishment of pathogens that can be transmitted during blood feeding. Methodology/Principal Findings We have obtained 1,626,969 reads by pyrosequencing a salivary gland cDNA library from adult females Amblyomma maculatum ticks at different times of feeding. Assembly of this data produced 72,441 sequences larger than 149 nucleotides from which 15,914 coding sequences were extracted. Of these, 5,353 had >75% coverage to their best match in the non-redundant database from the National Center for Biotechnology information, allowing for the deposition of 4,850 sequences to GenBank. The annotated data sets are available as hyperlinked spreadsheets. Putative secreted proteins were classified in 133 families, most of which have no known function. Conclusions/Significance This data set of proteins constitutes a mining platform for novel pharmacologically active proteins and for uncovering vaccine targets against A. maculatum and the diseases they carry.
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Francischetti IMB, Anderson JM, Manoukis N, Pham VM, Ribeiro JMC. An insight into the sialotranscriptome and proteome of the coarse bontlegged tick, Hyalomma marginatum rufipes. J Proteomics 2011; 74:2892-908. [PMID: 21851864 PMCID: PMC3215792 DOI: 10.1016/j.jprot.2011.07.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 07/11/2011] [Accepted: 07/13/2011] [Indexed: 01/28/2023]
Abstract
Ticks are mites specialized in acquiring blood from vertebrates as their sole source of food and are important disease vectors to humans and animals. Among the specializations required for this peculiar diet, ticks evolved a sophisticated salivary potion that can disarm their host's hemostasis, inflammation, and immune reactions. Previous transcriptome analysis of tick salivary proteins has revealed many new protein families indicative of fast evolution, possibly due to host immune pressure. The hard ticks (family Ixodidae) are further divided into two basal groups, of which the Metastriata have 11 genera. While salivary transcriptomes and proteomes have been described for some of these genera, no tick of the genus Hyalomma has been studied so far. The analysis of 2084 expressed sequence tags (EST) from a salivary gland cDNA library allowed an exploration of the proteome of this tick species by matching peptide ions derived from MS/MS experiments to this data set. We additionally compared these MS/MS derived peptide sequences against the proteins from the bovine host, finding many host proteins in the salivary glands of this tick. This annotated data set can assist the discovery of new targets for anti-tick vaccines as well as help to identify pharmacologically active proteins.
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Affiliation(s)
- Ivo MB Francischetti
- Section of Vector Biology, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville MD 20852, USA
| | - Jennifer M Anderson
- Section of Vector Biology, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville MD 20852, USA
| | - Nicholas Manoukis
- Section of Vector Biology, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville MD 20852, USA
| | - Van M Pham
- Section of Vector Biology, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville MD 20852, USA
| | - José MC Ribeiro
- Section of Vector Biology, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville MD 20852, USA
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Kang TS, Georgieva D, Genov N, Murakami MT, Sinha M, Kumar RP, Kaur P, Kumar S, Dey S, Sharma S, Vrielink A, Betzel C, Takeda S, Arni RK, Singh TP, Kini RM. Enzymatic toxins from snake venom: structural characterization and mechanism of catalysis. FEBS J 2011; 278:4544-76. [PMID: 21470368 DOI: 10.1111/j.1742-4658.2011.08115.x] [Citation(s) in RCA: 185] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Snake venoms are cocktails of enzymes and non-enzymatic proteins used for both the immobilization and digestion of prey. The most common snake venom enzymes include acetylcholinesterases, l-amino acid oxidases, serine proteinases, metalloproteinases and phospholipases A(2) . Higher catalytic efficiency, thermal stability and resistance to proteolysis make these enzymes attractive models for biochemists, enzymologists and structural biologists. Here, we review the structures of these enzymes and describe their structure-based mechanisms of catalysis and inhibition. Some of the enzymes exist as protein complexes in the venom. Thus we also discuss the functional role of non-enzymatic subunits and the pharmacological effects of such protein complexes. The structures of inhibitor-enzyme complexes provide ideal platforms for the design of potent inhibitors which are useful in the development of prototypes and lead compounds with potential therapeutic applications.
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Affiliation(s)
- Tse Siang Kang
- Department of Pharmacy, National University of Singapore, Singapore
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Comparison between apo and complexed structures of bothropstoxin-I reveals the role of Lys122 and Ca2+-binding loop region for the catalytically inactive Lys49-PLA2s. J Struct Biol 2010; 171:31-43. [DOI: 10.1016/j.jsb.2010.03.019] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 02/23/2010] [Accepted: 03/31/2010] [Indexed: 11/22/2022]
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Azevedo Calderon LD, Silva ADAE, Ciancaglini P, Stábeli RG. Antimicrobial peptides from Phyllomedusa frogs: from biomolecular diversity to potential nanotechnologic medical applications. Amino Acids 2010; 40:29-49. [PMID: 20526637 DOI: 10.1007/s00726-010-0622-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 05/05/2010] [Indexed: 10/19/2022]
Abstract
Screening for new bioactive peptides in South American anurans has been pioneered in frogs of the genus Phyllomedusa. All frogs of this genus have venomous skin secretions, i.e., a complex mixture of bioactive peptides against potential predators and pathogens that presumably evolved in a scenario of predator-prey interaction and defense against microbial invasion. For every new anuran species studied new peptides are found, with homologies to hormones, neurotransmitters, antimicrobials, and several other peptides with unknown biological activity. From Vittorio Erspamer findings, this genus has been reported as a "treasure store" of bioactive peptides, and several groups focus their research on these species. From 1966 to 2009, more than 200 peptide sequences from different Phyllomedusa species were deposited in UniProt and other databases. During the last decade, the emergence of high-throughput molecular technologies involving de novo peptide sequencing via tandem mass spectrometry, cDNA cloning, pharmacological screening, and surface plasmon resonance applied to peptide discovery, led to fast structural data acquisition and the generation of peptide molecular libraries. Research groups on bioactive peptides in Brazil using these new technologies, accounted for the exponential increase of new molecules described in the last decade, much higher than in any previous decades. Recently, these secretions were also reported as a rich source of multiple antimicrobial peptides effective against multidrug resistant strains of bacteria, fungi, protozoa, and virus, providing instructive lessons for the development of new and more efficient nanotechnological-based therapies for infectious diseases treatment. Therefore, novel drugs arising from the identification and analysis of bioactive peptides from South American anuran biodiversity have a promising future role on nanobiotechnology.
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Affiliation(s)
- Leonardo de Azevedo Calderon
- Centro de Estudos de Biomoléculas Aplicadas a Medicina "Professor Dr. José Roberto Giglio" (CEBio), Núcleo de Saúde (NUSAU), Universidade Federal de Rondônia (UNIR), Porto Velho, RO, 76800-000, Brazil
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Relationship between antibody 2F5 neutralization of HIV-1 and hydrophobicity of its heavy chain third complementarity-determining region. J Virol 2009; 84:2955-62. [PMID: 20042512 DOI: 10.1128/jvi.02257-09] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The membrane-proximal external region (MPER) of the HIV-1 gp41 transmembrane glycoprotein is the target of the broadly neutralizing antibody 2F5. Prior studies have suggested a two-component mechanism for 2F5-mediated neutralization involving both structure-specific recognition of a gp41 protein epitope and nonspecific interaction with the viral lipid membrane. Here, we mutationally alter a hydrophobic patch on the third complementarity-determining region of the heavy chain (CDR H3) of the 2F5 antibody and assess the abilities of altered 2F5 variants to bind gp41 and to neutralize diverse strains of HIV-1. CDR H3 alterations had little effect on the affinity of 2F5 variants for a peptide corresponding to its gp41 epitope. In contrast, strong effects and a high degree of correlation (P < 0.0001) were found between virus neutralization and CDR H3 hydrophobicity, as defined by predicted free energies of transfer from water to a lipid bilayer interface or to octanol. The effect of CDR H3 hydrophobicity on neutralization was independent of isolate sensitivity to 2F5, and CDR H3 variants with tryptophan substitutions were able to neutralize HIV-1 approximately 10-fold more potently than unmodified 2F5. A threshold was observed for increased hydrophobicity of the 2F5 CDR H3 loop beyond which effects on 2F5-mediated neutralization leveled off. Together, the results provide a more complete understanding of the 2F5 mechanism of HIV-1 neutralization and indicate ways to enhance the potency of MPER-directed antibodies.
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Doley R, Kini RM. Protein complexes in snake venom. Cell Mol Life Sci 2009; 66:2851-71. [PMID: 19495561 PMCID: PMC11115964 DOI: 10.1007/s00018-009-0050-2] [Citation(s) in RCA: 162] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 05/01/2009] [Accepted: 05/11/2009] [Indexed: 01/26/2023]
Abstract
Snake venom contains mixture of bioactive proteins and polypeptides. Most of these proteins and polypeptides exist as monomers, but some of them form complexes in the venom. These complexes exhibit much higher levels of pharmacological activity compared to individual components and play an important role in pathophysiological effects during envenomation. They are formed through covalent and/or non-covalent interactions. The subunits of the complexes are either identical (homodimers) or dissimilar (heterodimers; in some cases subunits belong to different families of proteins). The formation of complexes, at times, eliminates the non-specific binding and enhances the binding to the target molecule. On several occasions, it also leads to recognition of new targets as protein-protein interaction in complexes exposes the critical amino acid residues buried in the monomers. Here, we describe the structure and function of various protein complexes of snake venoms and their role in snake venom toxicity.
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Affiliation(s)
- R Doley
- Protein Science Laboratory, Department of Biological Sciences, Faculty of Science, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore.
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Doley R, Mackessy SP, Kini RM. Role of accelerated segment switch in exons to alter targeting (ASSET) in the molecular evolution of snake venom proteins. BMC Evol Biol 2009; 9:146. [PMID: 19563684 PMCID: PMC2711939 DOI: 10.1186/1471-2148-9-146] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Accepted: 06/30/2009] [Indexed: 11/19/2022] Open
Abstract
Background Snake venom toxins evolve more rapidly than other proteins through accelerated changes in the protein coding regions. Previously we have shown that accelerated segment switch in exons to alter targeting (ASSET) might play an important role in its functional evolution of viperid three-finger toxins. In this phenomenon, short sequences in exons are radically changed to unrelated sequences and hence affect the folding and functional properties of the toxins. Results Here we analyzed other snake venom protein families to elucidate the role of ASSET in their functional evolution. ASSET appears to be involved in the functional evolution of three-finger toxins to a greater extent than in several other venom protein families. ASSET leads to replacement of some of the critical amino acid residues that affect the biological function in three-finger toxins as well as change the conformation of the loop that is involved in binding to specific target sites. Conclusion ASSET could lead to novel functions in snake venom proteins. Among snake venom serine proteases, ASSET contributes to changes in three surface segments. One of these segments near the substrate binding region is known to affect substrate specificity, and its exchange may have significant implications for differences in isoform catalytic activity on specific target protein substrates. ASSET therefore plays an important role in functional diversification of snake venom proteins, in addition to accelerated point mutations in the protein coding regions. Accelerated point mutations lead to fine-tuning of target specificity, whereas ASSET leads to large-scale replacement of multiple functionally important residues, resulting in change or gain of functions.
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Affiliation(s)
- Robin Doley
- Department of Biological Sciences, National University of Singapore, Singapore.
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Paesen GC, Siebold C, Dallas ML, Peers C, Harlos K, Nuttall PA, Nunn MA, Stuart DI, Esnouf RM. An ion-channel modulator from the saliva of the brown ear tick has a highly modified Kunitz/BPTI structure. J Mol Biol 2009; 389:734-47. [PMID: 19394347 DOI: 10.1016/j.jmb.2009.04.045] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 04/17/2009] [Accepted: 04/21/2009] [Indexed: 12/17/2022]
Abstract
Ra-KLP, a 75 amino acid protein secreted by the salivary gland of the brown ear tick Rhipicephalus appendiculatus has a sequence resembling those of Kunitz/BPTI proteins. We report the detection, purification and characterization of the function of Ra-KLP. In addition, determination of the three-dimensional crystal structure of Ra-KLP at 1.6 A resolution using sulphur single-wavelength anomalous dispersion reveals that much of the loop structure of classical Kunitz domains, including the protruding protease-binding loop, has been replaced by beta-strands. Even more unusually, the N-terminal portion of the polypeptide chain is pinned to the "Kunitz head" by two disulphide bridges not found in classical Kunitz/BPTI proteins. The disulphide bond pattern has been further altered by the loss of the bridge that normally stabilizes the protease-binding loop. Consistent with the conversion of this loop into a beta-strand, Ra-KLP shows no significant anti-protease activity; however, it activates maxiK channels in an in vitro system, suggesting a potential mechanism for regulating host blood supply during feeding.
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Fry BG, Vidal N, van der Weerd L, Kochva E, Renjifo C. Evolution and diversification of the Toxicofera reptile venom system. J Proteomics 2009; 72:127-36. [DOI: 10.1016/j.jprot.2009.01.009] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Accepted: 01/12/2009] [Indexed: 11/25/2022]
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Liu WH, Kao PH, Lin SR, Chang LS. Membrane-damaging activity with A chain and B chain of β-bungarotoxin. Toxicon 2009; 53:262-8. [DOI: 10.1016/j.toxicon.2008.11.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2008] [Revised: 11/25/2008] [Accepted: 11/26/2008] [Indexed: 12/22/2022]
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Inagaki H, Akagi M, Imai HT, Taylor RW, Wiese MD, Davies NW, Kubo T. Pilosulin 5, a novel histamine-releasing peptide of the Australian ant, Myrmecia pilosula (Jack Jumper Ant). Arch Biochem Biophys 2008; 477:411-6. [DOI: 10.1016/j.abb.2008.05.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Accepted: 05/21/2008] [Indexed: 11/28/2022]
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Montecucco C, Rossetto O. On the quaternary structure of taipoxin and textilotoxin: The advantage of being multiple. Toxicon 2008; 51:1560-2. [DOI: 10.1016/j.toxicon.2008.03.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Revised: 03/18/2008] [Accepted: 03/19/2008] [Indexed: 10/22/2022]
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