1
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Salvador GHM, Pinto ÊKR, Ortolani PL, Fortes-Dias CL, Cavalcante WLG, Soares AM, Lomonte B, Lewin MR, Fontes MRM. Structural basis of the myotoxic inhibition of the Bothrops pirajai PrTX-I by the synthetic varespladib. Biochimie 2023; 207:1-10. [PMID: 36403756 DOI: 10.1016/j.biochi.2022.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 11/08/2022] [Accepted: 11/14/2022] [Indexed: 11/18/2022]
Abstract
Varespladib (LY315920) is a potent inhibitor of human group IIA phospholipase A2 (PLA2) originally developed to control inflammatory cascades of diseases associated with high or dysregulated levels of endogenous PLA2. Recently, varespladib was also found to inhibit snake venom PLA2 and PLA2-like toxins. Herein, ex vivo neuromuscular blocking activity assays were used to test the inhibitory activity of varespladib. The binding affinity between varespladib and a PLA2-like toxin was quantified and compared with other potential inhibitors for this class of proteins. Crystallographic and bioinformatic studies showed that varespladib binds to PrTX-I and BthTX-I into their hydrophobic channels, similarly to other previously characterized PLA2-like myotoxins. However, a new finding is that an additional varespladib binds to the MDiS region, a particular site that is related to muscle cell disruption by these toxins. The present results further advance the characterization of the molecular interactions of varespladib with PLA2-like myotoxins and provide additional evidence for this compound as a promising inhibitor candidate for different PLA2 and PLA2-like toxins.
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Affiliation(s)
- Guilherme H M Salvador
- Departamento de Biofísica e Farmacologia, Instituto de Biociências, Universidade Estadual Paulista, Botucatu, SP, Brazil
| | - Êmylle K R Pinto
- Departmento de Farmacologia, Instituto de Ciências Biologicas, Universidade Federal de Minas Gerais (UFMG), Brazil
| | - Paula L Ortolani
- Centro de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias (FUNED), Brazil
| | | | - Walter L G Cavalcante
- Departmento de Farmacologia, Instituto de Ciências Biologicas, Universidade Federal de Minas Gerais (UFMG), Brazil
| | - Andreimar M Soares
- Laboratório de Biotecnologia de Proteínas e Compostos Bioativos Aplicados à Saúde, LABIOPROT, Fundação Oswaldo Cruz, FIOCRUZ, unidade Rondônia e Instituto Nacional de Ciência e Tecnologia de Epidemiologia da Amazônia Ocidental, INCT EPIAMO, Porto Velho, RO, Brazil
| | - Bruno Lomonte
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Matthew R Lewin
- Ophirex, Inc. Corte Madera, CA, 94925, USA; Center for Exploration and Travel Health, California Academy of Sciences, San Francisco, CA, 94118, USA
| | - Marcos R M Fontes
- Departamento de Biofísica e Farmacologia, Instituto de Biociências, Universidade Estadual Paulista, Botucatu, SP, Brazil.
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2
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Structural and functional studies of a snake venom phospholipase A 2-like protein complexed to an inhibitor from Tabernaemontana catharinensis. Biochimie 2023; 206:105-115. [PMID: 36273763 DOI: 10.1016/j.biochi.2022.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/19/2022] [Accepted: 10/17/2022] [Indexed: 11/22/2022]
Abstract
Snake envenomation is an ongoing global health problem and tropical neglected disease that afflicts millions of people each year. The only specific treatment, antivenom, has several limitations that affects its proper distribution to the victims and its efficacy against local effects, such as myonecrosis. The main responsible for this consequence are the phospholipases A2 (PLA2) and PLA2-like proteins, such as BthTX-I from Bothrops jararacussu. Folk medicine resorts to plants such as Tabernaemontana catharinensis to palliate these and other snakebite effects. Here, we evaluated the effect of its root bark extract and one of its isolated compounds, 12-methoxy-4-methyl-voachalotine (MMV), against the in vitro paralysis and muscle damage induced by BthTX-I. Secondary and quaternary structures of BthTX-I were not modified by the interaction with MMV. Instead, this compound interacted in an unprecedented way with the region inside the toxin hydrophobic channel and promoted a structural change in Val31, loop 58-71 and Membrane Disruption Site. Thus, we hypothesize that MMV inhibits PLA2-like proteins by preventing entrance of fatty acid into the hydrophobic channel. These data may explain the traditional use of T. catharinensis extract and confirm MMV as a promising candidate to complement antivenom or a structural guide to develop more effective inhibitors.
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3
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Lomonte B. Lys49 myotoxins, secreted phospholipase A 2-like proteins of viperid venoms: A comprehensive review. Toxicon 2023; 224:107024. [PMID: 36632869 DOI: 10.1016/j.toxicon.2023.107024] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/06/2023] [Accepted: 01/06/2023] [Indexed: 01/11/2023]
Abstract
Muscle necrosis is a potential clinical complication of snakebite envenomings, which in severe cases can lead to functional or physical sequelae such as disability or amputation. Snake venom proteins with the ability to directly damage skeletal muscle fibers are collectively referred to as myotoxins, and include three main types: cytolysins of the "three-finger toxin" protein family expressed in many elapid venoms, the so-called "small" myotoxins found in a number of rattlesnake venoms, and the widespread secreted phospholipase A2 (sPLA2) molecules. Among the latter, protein variants that conserve the sPLA2 structure, but lack such enzymatic activity, have been increasingly found in the venoms of many viperid species. Intriguingly, these sPLA2-like proteins are able to induce muscle necrosis by a mechanism independent of phospholipid hydrolysis. They are commonly referred to as "Lys49 myotoxins" since they most often present, among other substitutions, the replacement of the otherwise invariant residue Asp49 of sPLA2s by Lys. This work comprehensively reviews the historical developments and current knowledge towards deciphering the mechanism of action of Lys49 sPLA2-like myotoxins, and points out main gaps to be filled for a better understanding of these multifaceted snake venom proteins, to hopefully lead to improved treatments for snakebites.
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Affiliation(s)
- Bruno Lomonte
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, 11501, Costa Rica.
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4
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Mei X, Luo W, Li H, Pu S. Synthesis and photophysical investigation of Schiff base as a Mg 2+ and Zn 2+ fluorescent chemosensor and its application. LUMINESCENCE 2023; 38:250-259. [PMID: 36649122 DOI: 10.1002/bio.4443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/14/2023] [Accepted: 01/14/2023] [Indexed: 01/18/2023]
Abstract
In view of the fluorescent switching properties and anti-fatigue properties of diarylethene, a diarylethene fluorescent chemosensor for the immediate detection of zinc ion (Zn2+ ) and magnesium ion (Mg2+ ) in acetonitrile was synthesized in this article. The structure of 1o was determined by performing spectroscopy and elemental analysis. The presence of Zn2+ or Mg2+ made the chemosensor 1o show an obvious "turn-on" fluorescent signal (bright yellow-green for Mg2+ and bright cyan for Zn2+ ). The fluorescent change caused by the 1:1 binding of 1o and Zn2+ or Mg2+ might be due to hindering the excited-state intramolecular proton transfer (ESIPT) process, which were bolstered by Benesi-Hildebrand analysis, Job's plot curves, proton nuclear magnetic resonance (1 H-NMR) titration and mass spectrometry. The limits of detection were acquired from the standard curve plots for Mg2+ at 44.6 nM and for Zn2+ at 14 nM. Based on the fluorescent behaviors, a logic gate was constructed with the emission intensity at 528/518 nm as output signal, the ultraviolet-visible (UV-vis) lights, Mg2+ /Zn2+ and EDTA as input signals. Exogenous Zn2+ and Mg2+ fluorescent bioimaging were performed on Hela cells with 1o, indicating its potential application in biodiagnostic analysis. In particular, 1o was manufactured into test paper, and Zn2+ or Mg2+ can be conveniently, efficiently and qualitatively identified by the fluorescent color variation of the test strips.
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Affiliation(s)
- Xin Mei
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang, P. R. China
| | - Wentao Luo
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang, P. R. China
| | - Hui Li
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang, P. R. China
| | - Shouzhi Pu
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang, P. R. China.,Department of Ecology and Environment, Yuzhang Normal University, Nanchang, P. R. China
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5
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BthTX-II from Bothrops jararacussu venom has variants with different oligomeric assemblies: An example of snake venom phospholipases A 2 versatility. Int J Biol Macromol 2021; 191:255-266. [PMID: 34547312 DOI: 10.1016/j.ijbiomac.2021.09.083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 09/10/2021] [Accepted: 09/13/2021] [Indexed: 10/20/2022]
Abstract
Phospholipases A2 (PLA2s) are found in almost every venomous snake family. In snakebites, some PLA2s can quickly cause local myonecrosis, which may lead to permanent sequelae if antivenom is administered belatedly. They hydrolyse phospholipids in membranes through a catalytic calcium ions-dependent mechanism. BthTX-II is a basic PLA2 and the second major component in the venom of Bothrops jararacussu. Herein, using the software SEQUENCE SLIDER, which integrates crystallographic, mass spectrometry and genetic data, we characterized the primary, tertiary and quaternary structure of two BthTX-II variants (called a and b), which diverge in 7 residues. Crystallographic structure BthTX-IIa is in a Tense-state with its distorted calcium binding loop buried in the dimer interface, contrarily, the novel BthTX-IIb structure is a monomer in a Relax-state with a fatty acid in the hydrophobic channel. Structural data in solution reveals that both variants are monomeric in neutral physiological conditions and mostly dimeric in an acidic environment, being catalytic active in both situations. Therefore, we propose two myotoxic mechanisms for BthTX-II, a catalytic one associated with the monomeric assembly, whereas the other has a calcium independent activity related to its C-terminal region, adopting a dimeric conformation similar to PLA2-like proteins.
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6
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Teixeira SC, da Silva MS, Gomes AAS, Moretti NS, Lopes DS, Ferro EAV, Rodrigues VDM. Panacea within a Pandora's box: the antiparasitic effects of phospholipases A 2 (PLA 2s) from snake venoms. Trends Parasitol 2021; 38:80-94. [PMID: 34364805 DOI: 10.1016/j.pt.2021.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 10/20/2022]
Abstract
Parasitic diseases affect millions of individuals worldwide, mainly in low-income regions. There is no cure for most of these diseases, and the treatment relies on drugs that have side effects and lead to drug resistance, emphasizing the urgency to find new treatments. Snake venom has been gaining prominence as a rich source of molecules with antiparasitic potentials, such as phospholipases A2 (PLA2s). Here, we compile the findings involving PLA2s with antiparasitic activities against helminths, Plasmodium, Toxoplasma, and trypanosomatids. We indicate their molecular features, highlighting the possible antiparasitic mechanisms of action of these proteins. We also demonstrate interactions between PLA2s and some parasite membrane components, shedding light on potential targets for drug design that may provide better treatment for the illnesses caused by parasites.
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Affiliation(s)
- Samuel Cota Teixeira
- Department of Immunology, Institute of Biomedical Science, Federal University of Uberlândia, Uberlândia (UFU), MG, Brazil.
| | - Marcelo Santos da Silva
- DNA Replication and Repair Laboratory (DRRL), Department of Chemical and Biological Sciences, Biosciences Institute, São Paulo State University (UNESP), Botucatu, SP, Brazil
| | | | - Nilmar Silvio Moretti
- Laboratório de Biologia Molecular de Patógenos (LBMP), Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Daiana Silva Lopes
- Multidisciplinary Institute of Health, Anísio Teixeira Campus, Federal University of Bahia (UFBA), Vitória da Conquista, BA, Brazil
| | - Eloisa Amália Vieira Ferro
- Department of Immunology, Institute of Biomedical Science, Federal University of Uberlândia, Uberlândia (UFU), MG, Brazil
| | - Veridiana de Melo Rodrigues
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia (UFU), Uberlândia, MG, Brazil.
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Wu Q, Feng L, Chao JB, Wang Y, Shuang S. Ratiometric sensing of Zn 2+ with a new benzothiazole-based fluorescent sensor and living cell imaging. Analyst 2021; 146:4348-4356. [PMID: 34113936 DOI: 10.1039/d1an00749a] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A new fluorescent probe, 3-(benzo[d]thiazol-2-yl)-5-bromosalicylaldehyde-4N-phenyl thiosemicarbazone (BTT), for ratiometric sensing of Zn2+ ions in methanol/HEPES buffer solution (3 : 2, pH = 7.4) is reported in this paper. The presence of Zn2+ ions yields a significant blue shift in the maximum emission of BTT from 570 nm to 488 nm, accompanied by a clear color change from orange to green. This emission change of BTT upon binding to Zn2+ in a 1 : 1 ratio may be due to the block of excited state intramolecular proton transfer (ESIPT) as well as chelation enhanced fluorescence (CHEF) on complex formation. The limit of detection (LOD) determined for Zn2+ quantitation was down to 37.7 nM. In addition, the probe BTT displays the ability to image both exogenous Zn2+ ions loaded into HeLa cells and endogenous Zn2+ distribution in living SH-SY5Y neuroblastoma cells.
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Affiliation(s)
- Qi Wu
- School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, PR China.
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8
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In-solution structural studies involving a phospholipase A 2-like myotoxin and a natural inhibitor: Plasticity of oligomeric assembly affects mechanisms of inhibition. Biochimie 2020; 181:145-153. [PMID: 33333169 DOI: 10.1016/j.biochi.2020.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 12/11/2020] [Accepted: 12/12/2020] [Indexed: 02/02/2023]
Abstract
Snakebite envenomation has been categorized by World Health Organization as a category A neglected tropical disease, since it causes chronic psychological disorders, physical disablement and death. Ophidian accidents may cause local myonecrosis that cause drastic sequelae, which are not efficiently neutralized via serum therapy. Phospholipase A2-like (PLA2-like) myotoxins have a major role in the local effects caused by several snake venoms. We previously demonstrated that chicoric acid (CA) is an efficient inhibitor of the BthTX-I myotoxin and solved the X-ray structure of complex. Herein, we assess the oligomeric behavior of the BthTX-I/CA complex in solution under different physical-chemical conditions and using toxin obtained by two different biochemical methodologies to fully elucidate structural bases of inhibition of myotoxins by CA. We demonstrated the ability of PLA2-like proteins to form different oligomeric assemblies in the presence of certain inhibitors, which can also be modulated by buffer polarity change. In the presence of ethanol, BthTX-I/CA remains predominantly in a monomeric conformation, which prevents it from being in its active form (dimeric conformation). In contrast, in the absence of ethanol, the tetramer assembly was observed, which hid key regions of the protein responsible for docking and disruption of the muscle membrane. Therefore, the "plasticity" of these proteins with regard to their abilities to form oligomeric assemblies is a key issue for the future development of therapeutic agents to complement of serum therapy.
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9
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The allosteric activation mechanism of a phospholipase A 2-like toxin from Bothrops jararacussu venom: a dynamic description. Sci Rep 2020; 10:16252. [PMID: 33004851 PMCID: PMC7529814 DOI: 10.1038/s41598-020-73134-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 08/24/2020] [Indexed: 11/08/2022] Open
Abstract
The activation process of phospholipase A2-like (PLA2-like) toxins is a key step in their molecular mechanism, which involves oligomeric changes leading to the exposure of specific sites. Few studies have focused on the characterization of allosteric activators and the features that distinguish them from inhibitors. Herein, a comprehensive study with the BthTX-I toxin from Bothrops jararacussu venom bound or unbound to α-tocopherol (αT) was carried out. The oligomerization state of BthTX-I bound or unbound to αT in solution was studied and indicated that the toxin is predominantly monomeric but tends to oligomerize when complexed with αT. In silico molecular simulations showed the toxin presents higher conformational changes in the absence of αT,
which suggests that it is important to stabilize the structure of the toxin. The transition between the two states (active/inactive) was also studied, showing that only the unbound BthTX-I system could migrate to the inactive state. In contrast, the presence of αT induces the toxin to leave the inactive state, guiding it towards the active state, with more regions exposed to the solvent, particularly its active site. Finally, the structural determinants necessary for a molecule to be an inhibitor or activator were analyzed in light of the obtained results.
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10
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Cardoso FF, Gomes AAS, Dreyer TR, Cavalcante WLG, Dal Pai M, Gallacci M, Fontes MRM. Neutralization of a bothropic PLA 2-like protein by caftaric acid, a novel potent inhibitor of ophidian myotoxicity. Biochimie 2020; 170:163-172. [PMID: 31978419 DOI: 10.1016/j.biochi.2020.01.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 01/19/2020] [Indexed: 11/18/2022]
Abstract
Envenoming by snakebite is an important global health issue that has received little attention, leading the World Health Organization to naming it as neglected tropical disease. Several snakebites present serious local symptoms manifested on victims that may not be efficiently neutralized by serum therapy. Phospholipase A2-like (PLA2-like) toxins are present in Viperidae venoms and are responsible for local myotoxic activity. Herein, we investigated the association between BthTX-I toxin and caftaric acid (CFT), a molecule present in plants. CFT neutralized neuromuscular blocking and muscle-damaging activities promoted by BthTX-I. Calorimetric and light-scattering assays demonstrated that CFT inhibitor interacted with dimeric BthTX-I. Bioinformatics simulations indicated that CFT inhibitor binds to the toxin's hydrophobic channel (HCh). According to the current myotoxic mechanism, three different regions of PLA2-like toxins have specific tasks: protein allosteric activation (HCh), membrane dockage (MDoS), and membrane rupture (MDiS). We propose CFT inhibitor interferes with the allosteric activation, which is related to the conformation change leading to the exposure/alignment of MDoS/MDiS region. This is the first report of a PLA2-like toxin fully inhibited by a compound that interacts only with its HCh region. Thus, CFT is a novel candidate to complement serum therapy and improve the treatment of snakebite.
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Affiliation(s)
- Fábio F Cardoso
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil
| | - Antoniel A S Gomes
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil
| | - Thiago R Dreyer
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil
| | - Walter L G Cavalcante
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil; Departamento de Farmacologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil
| | - Maeli Dal Pai
- Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil
| | - Márcia Gallacci
- Departamento de Farmacologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil
| | - Marcos R M Fontes
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil.
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Structural basis for phospholipase A 2-like toxin inhibition by the synthetic compound Varespladib (LY315920). Sci Rep 2019; 9:17203. [PMID: 31748642 PMCID: PMC6868273 DOI: 10.1038/s41598-019-53755-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 11/05/2019] [Indexed: 01/23/2023] Open
Abstract
The World Health Organization recently listed snakebite envenoming as a Neglected Tropical Disease, proposing strategies to significantly reduce the global burden of this complex pathology by 2030. In this context, effective adjuvant treatments to complement conventional antivenom therapy based on inhibitory molecules for specific venom toxins have gained renewed interest. Varespladib (LY315920) is a synthetic molecule clinically tested to block inflammatory cascades of several diseases associated with elevated levels of secreted phospholipase A2 (sPLA2). Most recently, Varespladib was tested against several whole snake venoms and isolated PLA2 toxins, demonstrating potent inhibitory activity. Herein, we describe the first structural and functional study of the complex between Varespladib and a PLA2-like snake venom toxin (MjTX-II). In vitro and in vivo experiments showed this compound’s capacity to inhibit the cytotoxic and myotoxic effects of MjTX-II from the medically important South American snake, Bothrops moojeni. Crystallographic and bioinformatics analyses revealed interactions of Varespladib with two specific regions of the toxin, suggesting inhibition occurs by physical blockage of its allosteric activation, preventing the alignment of its functional sites and, consequently, impairing its ability to disrupt membranes. Furthermore, based on the analysis of several crystallographic structures, a distinction between toxin activators and inhibitors is proposed.
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12
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Sobrinho J, Francisco A, Simões-Silva R, Kayano A, Ruiz Diaz JA, Garay AG, Arruda A, Ferreira A, Santos A, Luiz M, Teles C, Pereira S, Zanchi F, Calderon L, Zuliani J, Soares A. Antimyotoxic Activity of Synthetic Peptides Derived from Bothrops atrox Snake Gamma Phospholipase A2 Inhibitor Selected by Virtual Screening. Curr Top Med Chem 2019; 19:1952-1961. [DOI: 10.2174/1568026619666190725102812] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/13/2019] [Accepted: 07/04/2019] [Indexed: 11/22/2022]
Abstract
Background:
Several studies have aimed to identify molecules that inhibit the toxic actions
of snake venom phospholipases A2 (PLA2s). Studies carried out with PLA2 inhibitors (PLIs) have been
shown to be efficient in this assignment.
Objective:
This work aimed to analyze the interaction of peptides derived from Bothrops atrox PLIγ
(atPLIγ) with a PLA2 and to evaluate the ability of these peptides to reduce phospholipase and myotoxic
activities.
Methods:
Peptides were subjected to molecular docking with a homologous Lys49 PLA2 from B. atrox
venom modeled by homology. Phospholipase activity neutralization assay was performed with BthTX-II
and different ratios of the peptides. A catalytically active and an inactive PLA2 were purified from the B.
atrox venom and used together in the in vitro myotoxic activity neutralization experiments with the peptides.
Results:
The peptides interacted with amino acids near the PLA2 hydrophobic channel and the loop that
would be bound to calcium in Asp49 PLA2. They were able to reduce phospholipase activity and peptides
DFCHNV and ATHEE reached the highest reduction levels, being these two peptides the best that
also interacted in the in silico experiments. The peptides reduced the myotubes cell damage with a highlight
for the DFCHNV peptide, which reduced by about 65%. It has been suggested that myotoxic activity
reduction is related to the sites occupied in the PLA2 structure, which could corroborate the results
observed in molecular docking.
Conclusion:
This study should contribute to the investigation of the potential of PLIs to inhibit the toxic
effects of PLA2s.
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Affiliation(s)
- J.C. Sobrinho
- Centro de Estudos de Biomoléculas Aplicadas à Saúde, CEBio, Fundação Oswaldo Cruz, FIOCRUZ, Fiocruz Rondônia, Brazil
| | - A.F. Francisco
- Centro de Estudos de Biomoléculas Aplicadas à Saúde, CEBio, Fundação Oswaldo Cruz, FIOCRUZ, Fiocruz Rondônia, Brazil
| | - R. Simões-Silva
- Centro de Estudos de Biomoléculas Aplicadas à Saúde, CEBio, Fundação Oswaldo Cruz, FIOCRUZ, Fiocruz Rondônia, Brazil
| | - A.M. Kayano
- Centro de Estudos de Biomoléculas Aplicadas à Saúde, CEBio, Fundação Oswaldo Cruz, FIOCRUZ, Fiocruz Rondônia, Brazil
| | - J.J. Alfonso Ruiz Diaz
- Centro de Estudos de Biomoléculas Aplicadas à Saúde, CEBio, Fundação Oswaldo Cruz, FIOCRUZ, Fiocruz Rondônia, Brazil
| | - A.F. Gomez Garay
- Centro de Estudos de Biomoléculas Aplicadas à Saúde, CEBio, Fundação Oswaldo Cruz, FIOCRUZ, Fiocruz Rondônia, Brazil
| | - A. Arruda
- Laboratório de Engenharia de Anticorpos, Fiocruz Rondônia, Porto Velho-RO, Brazil
| | - A.S. Ferreira
- Laboratório da Plataforma de Bioensaios de Malária e Leishmaniose, Fiocruz Rondônia, Porto Velho-RO, Brazil
| | - A.P.A. Santos
- Laboratório da Plataforma de Bioensaios de Malária e Leishmaniose, Fiocruz Rondônia, Porto Velho-RO, Brazil
| | - M.B. Luiz
- Laboratório de Engenharia de Anticorpos, Fiocruz Rondônia, Porto Velho-RO, Brazil
| | - C.B.G. Teles
- Laboratório da Plataforma de Bioensaios de Malária e Leishmaniose, Fiocruz Rondônia, Porto Velho-RO, Brazil
| | - S.S. Pereira
- Laboratório de Engenharia de Anticorpos, Fiocruz Rondônia, Porto Velho-RO, Brazil
| | - F.B. Zanchi
- Centro de Estudos de Biomoléculas Aplicadas à Saúde, CEBio, Fundação Oswaldo Cruz, FIOCRUZ, Fiocruz Rondônia, Brazil
| | - L.A. Calderon
- Centro de Estudos de Biomoléculas Aplicadas à Saúde, CEBio, Fundação Oswaldo Cruz, FIOCRUZ, Fiocruz Rondônia, Brazil
| | - J.P. Zuliani
- Centro de Estudos de Biomoléculas Aplicadas à Saúde, CEBio, Fundação Oswaldo Cruz, FIOCRUZ, Fiocruz Rondônia, Brazil
| | - A.M. Soares
- Centro de Estudos de Biomoléculas Aplicadas à Saúde, CEBio, Fundação Oswaldo Cruz, FIOCRUZ, Fiocruz Rondônia, Brazil
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Bouley RA, Hinkovska-Galcheva V, Shayman JA, Tesmer JJG. Structural Basis of Lysosomal Phospholipase A 2 Inhibition by Zn 2. Biochemistry 2019; 58:1709-1717. [PMID: 30830753 DOI: 10.1021/acs.biochem.8b01124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lysosomal phospholipase A2 (LPLA2/PLA2G15) is a key enzyme involved in lipid homeostasis and is characterized by both phospholipase A2 and transacylase activity and by an acidic pH optimum. Divalent cations such as Ca2+ and Mg2+ have previously been shown to have little effect on the activity of LPLA2, but the discovery of a novel crystal form of LPLA2 with Zn2+ bound in the active site suggested a role for this divalent cation in regulating enzyme activity. In this complex, the cation directly coordinates the serine and histidine of the α/β-hydrolase triad and stabilizes a closed conformation. This closed conformation is characterized by an inward shift of the lid loop, which extends over the active site and effectively blocks access to one of its lipid acyl chain binding tracks. Therefore, we hypothesized that Zn2+ would inhibit LPLA2 activity at a neutral but not acidic pH because histidine would be positively charged at lower pH. Indeed, Zn2+ was found to inhibit the esterase activity of LPLA2 in a noncompetitive manner exclusively at a neutral pH (between 6.5 and 8.0). Because lysosomes are reservoirs of Zn2+ in cells, the pH optimum of LPLA2 might allow it to catalyze acyl transfer unimpeded within the organelle. We conjecture that Zn2+ inhibition of LPLA2 at higher pH maintains a lower activity of the esterase in environments where its activity is not typically required.
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Affiliation(s)
- Renee A Bouley
- Life Sciences Institute and Department of Pharmacology , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Vania Hinkovska-Galcheva
- Department of Internal Medicine, University of Michigan Medical School , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - James A Shayman
- Department of Internal Medicine, University of Michigan Medical School , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - John J G Tesmer
- Departments of Biological Sciences and of Medicinal Chemistry & Molecular Pharmacology , Purdue University , West Lafayette , Indiana 47907 , United States
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Insights into individual variations in nematocyst venoms from the giant jellyfish Nemopilema nomurai in the Yellow Sea. Sci Rep 2019; 9:3361. [PMID: 30833625 PMCID: PMC6399247 DOI: 10.1038/s41598-019-40109-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 01/22/2019] [Indexed: 12/16/2022] Open
Abstract
The giant jellyfish, Nemopilema nomurai, is widely distributed from the Eastern China Sea to the northern part of the Yellow Sea and has resulted in numerous hospitalizations in coastal areas of China, especially in Northern China. Our previous studies have revealed sting-related proteins in the venom of the jellyfish N. nomurai by using experimental and omics-based approaches; however, the variable symptoms of patients who have been stung by N. nomurai are not fully understood. This limited knowledge led to an examination of whether intraspecific variations occur in the venom of different N. nomurai. In the present study, 13 specimens of N. nomurai were collected from the Yellow Sea, and their venom was characterized by profiling differences in biochemical properties and biological activities. SDS-PAGE analysis presented recognizable differences in the number, intensity and presence of some protein bands. Moreover, enzymatic assays revealed considerable quantitative variations in metalloproteinase activity and PLA2-like activity. In particular, zymography assays of proteases demonstrated the general presence of abundant metalloproteinases in jellyfish nematocyst venom; however, the catalytic activities varied greatly among some specific metalloproteinases in the 28–46 kDa or 57–83 kDa range. Hemolytic assays using sheep erythrocytes suggested a predominant variance in the toxicities of different individual jellyfish venoms, with the difference between the most hemolytic and the least hemolytic venom as large as 77-fold. The current data suggested remarkable variations in the nematocyst venoms of individual N. nomurai jellyfish. These observations will provide a new understanding of the clinical manifestations induced by N. nomurai jellyfish stings and will therefore have important implications for preventing and treating jellyfish envenomations.
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Salvador GHM, Cardoso FF, Gomes AA, Cavalcante WLG, Gallacci M, Fontes MRM. Search for efficient inhibitors of myotoxic activity induced by ophidian phospholipase A 2-like proteins using functional, structural and bioinformatics approaches. Sci Rep 2019; 9:510. [PMID: 30679550 PMCID: PMC6346006 DOI: 10.1038/s41598-018-36839-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 11/29/2018] [Indexed: 02/01/2023] Open
Abstract
Ophidian accidents are considered an important neglected tropical disease by the World Health Organization. Particularly in Latin America, Bothrops snakes are responsible for the majority of the snakebite envenomings that are not efficiently treated by conventional serum therapy. Thus, the search for simple and efficient inhibitors to complement this therapy is a promising research area, and a combination of functional and structural assays have been used to test candidate ligands against specific ophidian venom compounds. Herein, we tested a commercial drug (acetylsalicylic acid, ASA) and a plant compound with antiophidian properties (rosmarinic acid, RA) using myographic, crystallographic and bioinformatics experiments with a phospholipase A2-like toxin, MjTX-II. MjTX-II/RA and MjTX-II/ASA crystal structures were solved at high resolution and revealed the presence of ligands bound to different regions of the toxin. However, in vitro myographic assays showed that only RA is able to prevent the myotoxic effects of MjTX-II. In agreement with functional results, molecular dynamics simulations showed that the RA molecule remains tightly bound to the toxin throughout the calculations, whereas ASA molecules tend to dissociate. This approach aids the design of effective inhibitors of PLA2-like toxins and, eventually, may complement serum therapy.
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Affiliation(s)
- Guilherme H M Salvador
- Depto. de Física e Biofísica, Instituto de Biociências, UNESP - Universidade Estadual Paulista, Botucatu, SP, Brazil
| | - Fábio Florença Cardoso
- Depto. de Física e Biofísica, Instituto de Biociências, UNESP - Universidade Estadual Paulista, Botucatu, SP, Brazil
| | - Antoniel A Gomes
- Depto. de Física e Biofísica, Instituto de Biociências, UNESP - Universidade Estadual Paulista, Botucatu, SP, Brazil
| | - Walter L G Cavalcante
- Depto. de Física e Biofísica, Instituto de Biociências, UNESP - Universidade Estadual Paulista, Botucatu, SP, Brazil
- Depto. de Farmacologia, UFMG - Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Márcia Gallacci
- Depto. de Farmacologia, Instituto de Biociências, UNESP - Universidade Estadual Paulista, Botucatu, SP, Brazil
| | - Marcos R M Fontes
- Depto. de Física e Biofísica, Instituto de Biociências, UNESP - Universidade Estadual Paulista, Botucatu, SP, Brazil.
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Cardoso FF, Borges RJ, Dreyer TR, Salvador GH, Cavalcante WL, Pai MD, Gallacci M, Fontes MR. Structural basis of phospholipase A2-like myotoxin inhibition by chicoric acid, a novel potent inhibitor of ophidian toxins. Biochim Biophys Acta Gen Subj 2018; 1862:2728-2737. [DOI: 10.1016/j.bbagen.2018.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/30/2018] [Accepted: 08/01/2018] [Indexed: 10/28/2022]
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Structural and functional characterization of suramin-bound MjTX-I from Bothrops moojeni suggests a particular myotoxic mechanism. Sci Rep 2018; 8:10317. [PMID: 29985425 PMCID: PMC6037679 DOI: 10.1038/s41598-018-28584-7] [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: 03/16/2018] [Accepted: 06/26/2018] [Indexed: 11/25/2022] Open
Abstract
Local myonecrosis is the main event resulting from snakebite envenomation by the Bothrops genus and, frequently, it is not efficiently neutralized by antivenom administration. Proteases, phospholipases A2 (PLA2) and PLA2-like toxins are found in venom related to muscle damage. Functional sites responsible for PLA2-like toxins activity have been proposed recently; they consist of a membrane docking-site and a membrane rupture-site. Herein, a combination of functional, biophysical and crystallographic techniques was used to characterize the interaction between suramin and MjTX-I (a PLA2-like toxin from Bothrops moojeni venom). Functional in vitro neuromuscular assays were performed to study the biological effects of the protein-ligand interaction, demonstrating that suramin neutralizes the myotoxic effect of MjTX-I. Calorimetric assays showed two different binding events: (i) inhibitor-protein interactions and (ii) toxin oligomerization processes. These hypotheses were also corroborated with dynamic light and small angle X-ray scattering assays. The crystal structure of the MjTX-I/suramin showed a totally different interaction mode compared to other PLA2-like/suramin complexes. Thus, we suggested a novel myotoxic mechanism for MjTX-I that may be inhibited by suramin. These results can further contribute to the search for inhibitors that will efficiently counteract local myonecrosis in order to be used as an adjuvant of conventional serum therapy.
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Salvador GH, dos Santos JI, Borges RJ, Fontes MR. Structural evidence for a fatty acid-independent myotoxic mechanism for a phospholipase A2-like toxin. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:473-481. [DOI: 10.1016/j.bbapap.2017.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 10/18/2022]
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Secreted Phospholipases A₂ from Animal Venoms in Pain and Analgesia. Toxins (Basel) 2017; 9:toxins9120406. [PMID: 29311537 PMCID: PMC5744126 DOI: 10.3390/toxins9120406] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/13/2017] [Accepted: 12/16/2017] [Indexed: 12/20/2022] Open
Abstract
Animal venoms comprise a complex mixture of components that affect several biological systems. Based on the high selectivity for their molecular targets, these components are also a rich source of potential therapeutic agents. Among the main components of animal venoms are the secreted phospholipases A2 (sPLA2s). These PLA2 belong to distinct PLA2s groups. For example, snake venom sPLA2s from Elapidae and Viperidae families, the most important families when considering envenomation, belong, respectively, to the IA and IIA/IIB groups, whereas bee venom PLA2 belongs to group III of sPLA2s. It is well known that PLA2, due to its hydrolytic activity on phospholipids, takes part in many pathophysiological processes, including inflammation and pain. Therefore, secreted PLA2s obtained from animal venoms have been widely used as tools to (a) modulate inflammation and pain, uncovering molecular targets that are implicated in the control of inflammatory (including painful) and neurodegenerative diseases; (b) shed light on the pathophysiology of inflammation and pain observed in human envenomation by poisonous animals; and, (c) characterize molecular mechanisms involved in inflammatory diseases. The present review summarizes the knowledge on the nociceptive and antinociceptive actions of sPLA2s from animal venoms, particularly snake venoms.
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PLA 2-like proteins myotoxic mechanism: a dynamic model description. Sci Rep 2017; 7:15514. [PMID: 29138410 PMCID: PMC5686144 DOI: 10.1038/s41598-017-15614-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 10/19/2017] [Indexed: 11/23/2022] Open
Abstract
Phospholipase A2-like (PLA2-like) proteins contribute to the development of muscle necrosis in Viperidae snake bites and are not efficiently neutralized by current antivenom treatments. The toxic mechanisms of PLA2-like proteins are devoid of catalytic activity and not yet fully understood, although structural and functional experiments suggest a dimeric assembly and that the C-terminal residues are essential to myotoxicity. Herein, we characterized the functional mechanism of bothropic PLA2-like structures related to global and local measurements using the available models in the Protein Data Bank and normal mode molecular dynamics (NM-MD). Those measurements include: (i) new geometric descriptions between their monomers, based on Euler angles; (ii) characterizations of canonical and non-canonical conformations of the C-terminal residues; (iii) accessibility of the hydrophobic channel; (iv) inspection of ligands; and (v) distance of clustered residues to toxin interface of interaction. Thus, we described the allosteric activation of PLA2-like proteins and hypothesized that the natural movement between monomers, calculated from NM-MD, is related to their membrane disruption mechanism, which is important for future studies of the inhibition process. These methods and strategies can be applied to other proteins to help understand their mechanisms of action.
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Structural studies with BnSP-7 reveal an atypical oligomeric conformation compared to phospholipases A2-like toxins. Biochimie 2017; 142:11-21. [DOI: 10.1016/j.biochi.2017.07.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/21/2017] [Indexed: 12/21/2022]
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Crystal structure of a phospholipase A 2 from Bothrops asper venom: Insights into a new putative "myotoxic cluster". Biochimie 2016; 133:95-102. [PMID: 28034717 DOI: 10.1016/j.biochi.2016.12.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 12/20/2016] [Accepted: 12/23/2016] [Indexed: 11/20/2022]
Abstract
Snake venoms from the Viperidae and Elapidae families often have several phospholipases A2 (PLA2s), which may display different functions despite having a similar structural scaffold. These proteins are considered an important target for the development of drugs against local myotoxic damage because they are not efficiently neutralized by conventional serum therapy. PLA2s from these venoms are generally divided into two classes: (i) catalytic PLA2s (or Asp49-PLA2s) and (ii) non-catalytic PLA2-like toxins (or Lys49-PLA2s). In many Viperidae venoms, a subset of the basic Asp49-PLA2s displays some functional and structural characteristics of PLA2-like proteins and group within the same phylogenetic clade, but their myotoxic mechanism is still largely unknown. In the present study, we have crystallized and solved the structure of myotoxin I (MT-I), a basic myotoxic Asp49-PLA2 isolated from Bothrops asper venom. The structure presents a dimeric conformation that is compatible with that of previous dimers found for basic myotoxic Asp49-PLA2s and Lys49-PLA2s and has been confirmed by other biophysical and bioinformatics techniques. This arrangement suggests a possible cooperative action between both monomers to exert myotoxicity via two different sites forming a putative membrane-docking site (MDoS) and a putative membrane disruption site (MDiS). This mechanism would resemble that proposed for Lys49-PLA2s, but the sites involved appear to be situated in a different region. Thus, as both sites are close to one another, they form a "myotoxic cluster", which is also found in two other basic myotoxic Asp49-PLA2s from Viperidae venoms. Such arrangement may represent a novel structural strategy for the mechanism of muscle damage exerted by the group of basic, Asp49-PLA2s found in viperid snake venoms.
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