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Salvador GHM, Cardoso FF, Lomonte B, Fontes MRM. Inhibitors and activators for myotoxic phospholipase A 2-like toxins from snake venoms - A structural overview. Biochimie 2024:S0300-9084(24)00175-5. [PMID: 39089640 DOI: 10.1016/j.biochi.2024.07.016] [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: 04/10/2024] [Revised: 06/27/2024] [Accepted: 07/29/2024] [Indexed: 08/04/2024]
Abstract
Snakebite envenomations result in acute and chronic physical and psychological health effects on their victims, leading to a substantial socio-economic burden in tropical and subtropical countries. Local necrosis is one of the serious effects caused by envenomation, primarily induced by snake venoms from the Viperidae family through the direct action of components collectively denominated as myotoxins, including the phopholipase A2-like (PLA2-like) toxins. Considering the limitations of antivenoms in preventing the rapid development of local tissue damage caused by envenomation, the use of small molecule therapeutics has been suggested as potential first-aid treatments or as adjuvants to antivenom therapy. In this review, we provide an overview of the structural interactions of molecules exhibiting inhibitory activity toward PLA2-like toxins. Additionally, we discuss the implications for the myotoxic mechanism of PLA2-like toxins and the molecules involved in their activation, highlighting key differences between activators and inhibitors. Finally, we integrate all these results to propose a classification of inhibitors into three different classes and five sub-classes. Taking into account the structural and affinity information, we compare the different inhibitors/ligands to gain a deeper understanding of the structural basis for the effective inhibition of PLA2-like toxins. By offering these insights, we aim to contribute to the search for new and efficient inhibitor molecules to complement and improve current therapy by conventional antivenoms.
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Affiliation(s)
- Guilherme H M Salvador
- Departamento de Biofísica e Farmacologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu-SP, Brazil
| | - Fábio F Cardoso
- Departamento de Biofísica e Farmacologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu-SP, Brazil
| | - Bruno Lomonte
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Marcos R M Fontes
- Departamento de Biofísica e Farmacologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu-SP, Brazil; Instituto de Estudos Avançados do Mar (IEAMar), Universidade Estadual Paulista (UNESP), São Vicente-SP, Brazil.
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2
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de Oliveira ALN, Lacerda MT, Ramos MJ, Fernandes PA. Viper Venom Phospholipase A2 Database: The Structural and Functional Anatomy of a Primary Toxin in Envenomation. Toxins (Basel) 2024; 16:71. [PMID: 38393149 PMCID: PMC10893444 DOI: 10.3390/toxins16020071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/04/2024] [Accepted: 01/13/2024] [Indexed: 02/25/2024] Open
Abstract
Viper venom phospholipase A2 enzymes (vvPLA2s) and phospholipase A2-like (PLA2-like) proteins are two of the principal toxins in viper venom that are responsible for the severe myotoxic and neurotoxic effects caused by snakebite envenoming, among other pathologies. As snakebite envenoming is the deadliest neglected tropical disease, a complete understanding of these proteins' properties and their mechanisms of action is urgently needed. Therefore, we created a database comprising information on the holo-form, cofactor-bound 3D structure of 217 vvPLA2 and PLA2-like proteins in their physiologic environment, as well as 79 membrane-bound viper species from 24 genera, which we have made available to the scientific community to accelerate the development of new anti-snakebite drugs. In addition, the analysis of the sequenced, 3D structure of the database proteins reveals essential aspects of the anatomy of the proteins, their toxicity mechanisms, and the conserved binding site areas that may anchor universal interspecific inhibitors. Moreover, it pinpoints hypotheses for the molecular origin of the myotoxicity of the PLA2-like proteins. Altogether, this study provides an understanding of the diversity of these toxins and how they are conserved, and it indicates how to develop broad, interspecies, efficient small-molecule inhibitors to target the toxin's many mechanisms of action.
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Affiliation(s)
| | | | | | - Pedro A. Fernandes
- Requimte-Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-000 Porto, Portugal; (A.L.N.d.O.); (M.T.L.); (M.J.R.)
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3
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Belchor MN, Costa CRDC, Roggero A, Moraes LLF, Samelo R, Annunciato I, de Oliveira MA, Sousa SF, Toyama MH. In Silico Evaluation of Quercetin Methylated Derivatives on the Interaction with Secretory Phospholipases A2 from Crotalus durissus terrificus and Bothrops jararacussu. Pharmaceuticals (Basel) 2023; 16:ph16040597. [PMID: 37111354 PMCID: PMC10143728 DOI: 10.3390/ph16040597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/07/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023] Open
Abstract
Quercetin derivatives have already shown their anti-inflammatory potential, inhibiting essential enzymes involved in this process. Among diverse pro-inflammatory toxins from snake venoms, phospholipase A2 is one of the most abundant in some species, such as Crotalus durissus terrificus and Bothrops jararacussu from the Viperidae family. These enzymes can induce the inflammatory process through hydrolysis at the sn-2 position of glycerophospholipids. Hence, elucidating the main residues involved in the biological effects of these macromolecules can help to identify potential compounds with inhibitory activity. In silico tools were used in this study to evaluate the potential of quercetin methylated derivatives in the inhibition of bothropstoxin I (BthTX-I) and II (BthTX-II) from Bothrops jararacussu and phospholipase A2 from Crotalus durissus terrificus. The use of a transitional analogous and two classical inhibitors of phospholipase A2 guided this work to find the role of residues involved in the phospholipid anchoring and the subsequent development of the inflammatory process. First, main cavities were studied, revealing the best regions to be inhibited by a compound. Focusing on these regions, molecular docking assays were made to show main interactions between each compound. Results reveal that analogue and inhibitors, Varespladib (Var) and p-bromophenacyl bromide (BPB), guided quercetins derivatives analysis, revealing that Leu2, Phe5, Tyr28, glycine in the calcium-binding loop, His48, Asp49 of BthTX-II and Cdtspla2 were the main residues to be inhibited. 3MQ exhibited great interaction with the active site, similar to Var results, while Q anchored better in the BthTX-II active site. However, strong interactions in the C-terminal region, highlighting His120, seem to be crucial to decreasing contacts with phospholipid and BthTX-II. Hence, quercetin derivatives anchor differently with each toxin and further in vitro and in vivo studies are essential to elucidate these data.
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Affiliation(s)
- Mariana Novo Belchor
- Center of Natural and Human Sciences, Federal University of ABC (UFABC), Santo André 09210-580, SP, Brazil
- Biosciences Institute of Paulista Coast Campus (IB/CLP), University of São Paulo State (UNESP), São Vicente 11330-900, SP, Brazil
| | - Caroline Ramos da Cruz Costa
- Center of Natural and Human Sciences, Federal University of ABC (UFABC), Santo André 09210-580, SP, Brazil
- Biosciences Institute of Paulista Coast Campus (IB/CLP), University of São Paulo State (UNESP), São Vicente 11330-900, SP, Brazil
| | - Airam Roggero
- Biosciences Institute of Paulista Coast Campus (IB/CLP), University of São Paulo State (UNESP), São Vicente 11330-900, SP, Brazil
| | - Laila L F Moraes
- Biosciences Institute of Paulista Coast Campus (IB/CLP), University of São Paulo State (UNESP), São Vicente 11330-900, SP, Brazil
| | - Ricardo Samelo
- Biosciences Institute of Paulista Coast Campus (IB/CLP), University of São Paulo State (UNESP), São Vicente 11330-900, SP, Brazil
| | - Isabelly Annunciato
- Biosciences Institute of Paulista Coast Campus (IB/CLP), University of São Paulo State (UNESP), São Vicente 11330-900, SP, Brazil
| | - Marcos Antonio de Oliveira
- Center of Natural and Human Sciences, Federal University of ABC (UFABC), Santo André 09210-580, SP, Brazil
- Biosciences Institute of Paulista Coast Campus (IB/CLP), University of São Paulo State (UNESP), São Vicente 11330-900, SP, Brazil
| | - Sergio F Sousa
- Unit of Applied Biomolecular Sciences (UCIBIO), REQUIMTE-BioSIM-Medicine Faculty, Porto University, 4050-345 Porto, Portugal
| | - Marcos Hikari Toyama
- Center of Natural and Human Sciences, Federal University of ABC (UFABC), Santo André 09210-580, SP, Brazil
- Biosciences Institute of Paulista Coast Campus (IB/CLP), University of São Paulo State (UNESP), São Vicente 11330-900, SP, Brazil
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Bénard-Valle M, Neri-Castro E, Yañez-Mendoza MF, Lomonte B, Olvera A, Zamudio F, Restano-Cassulini R, Possani LD, Jiménez-Ferrer E, Alagón A. Functional, proteomic and transcriptomic characterization of the venom from Micrurus browni browni: Identification of the first lethal multimeric neurotoxin in coral snake venom. J Proteomics 2020; 225:103863. [DOI: 10.1016/j.jprot.2020.103863] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 05/18/2020] [Accepted: 06/04/2020] [Indexed: 10/24/2022]
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Resende L, Almeida J, Schezaro-Ramos R, Collaço R, Simioni L, Ramírez D, González W, Soares A, Calderon L, Marangoni S, da Silva S. Exploring and understanding the functional role, and biochemical and structural characteristics of an acidic phospholipase A2, AplTx-I, purified from Agkistrodon piscivorus leucostoma snake venom. Toxicon 2017; 127:22-36. [DOI: 10.1016/j.toxicon.2017.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Revised: 11/28/2016] [Accepted: 01/03/2017] [Indexed: 12/15/2022]
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Fernandes CA, Borges RJ, Lomonte B, Fontes MR. A structure-based proposal for a comprehensive myotoxic mechanism of phospholipase A2-like proteins from viperid snake venoms. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:2265-76. [DOI: 10.1016/j.bbapap.2014.09.015] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 09/09/2014] [Accepted: 09/16/2014] [Indexed: 01/21/2023]
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Mora-Obando D, Díaz C, Angulo Y, Gutiérrez JM, Lomonte B. Role of enzymatic activity in muscle damage and cytotoxicity induced by Bothrops asper Asp49 phospholipase A2 myotoxins: are there additional effector mechanisms involved? PeerJ 2014; 2:e569. [PMID: 25276503 PMCID: PMC4178460 DOI: 10.7717/peerj.569] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 08/20/2014] [Indexed: 01/15/2023] Open
Abstract
Viperid venoms often contain mixtures of Asp49 and Lys49 PLA2 myotoxin isoforms, relevant to development of myonecrosis. Given their difference in catalytic activity, mechanistic studies on each type require highly purified samples. Studies on Asp49 PLA2s have shown that enzyme inactivation using p-bromophenacyl bromide (p-BPB) drastically affects toxicity. However, based on the variable levels of residual toxicity observed in some studies, it has been suggested that effector mechanisms independent of catalysis may additionally be involved in the toxicity of these enzymes, possibly resembling those of the enzymatically inactive Lys49 myotoxins. A possibility that Lys49 isoforms could be present in Asp49 PLA2 preparations exists and, if undetected in previous studies, could explain the variable residual toxicity. This question is here addressed by using an enzyme preparation ascertained to be free of Lys49 myotoxins. In agreement with previous reports, inactivation of the catalytic activity of an Asp49 myotoxin preparation led to major inhibition of toxic effects in vitro and in vivo. The very low residual levels of myotoxicity (7%) and cytotoxicity (4%) observed can be attributed to the low, although detectable, enzyme remaining active after p-BPB treatment (2.7%), and would be difficult to reconcile with the proposed existence of additional catalytic-independent toxic mechanisms. These findings favor the concept that the effector mechanism of toxicity of Asp49 PLA2 myotoxins from viperids fundamentally relies on their ability to hydrolyze phospholipids, arguing against the proposal that membrane disruption may also be caused by additional mechanisms that are independent of catalysis.
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Affiliation(s)
- Diana Mora-Obando
- Instituto Clodomiro Picado, Facultad de Microbiologia, Universidad de Costa Rica , San José , Costa Rica
| | - Cecilia Díaz
- Instituto Clodomiro Picado, Facultad de Microbiologia, Universidad de Costa Rica , San José , Costa Rica ; Departamento de Bioquímica, Escuela de Medicina, Universidad de Costa Rica , San José , Costa Rica
| | - Yamileth Angulo
- Instituto Clodomiro Picado, Facultad de Microbiologia, Universidad de Costa Rica , San José , Costa Rica
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiologia, Universidad de Costa Rica , San José , Costa Rica
| | - Bruno Lomonte
- Instituto Clodomiro Picado, Facultad de Microbiologia, Universidad de Costa Rica , San José , Costa Rica
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Lee LK, Bryant KJ, Bouveret R, Lei PW, Duff AP, Harrop SJ, Huang EP, Harvey RP, Gelb MH, Gray PP, Curmi PM, Cunningham AM, Church WB, Scott KF. Selective inhibition of human group IIA-secreted phospholipase A2 (hGIIA) signaling reveals arachidonic acid metabolism is associated with colocalization of hGIIA to vimentin in rheumatoid synoviocytes. J Biol Chem 2013; 288:15269-79. [PMID: 23482564 PMCID: PMC3663547 DOI: 10.1074/jbc.m112.397893] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 03/06/2013] [Indexed: 11/06/2022] Open
Abstract
Human group IIA secreted phospholipase A2 (hGIIA) promotes tumor growth and inflammation and can act independently of its well described catalytic lipase activity via an alternative poorly understood signaling pathway. With six chemically diverse inhibitors we show that it is possible to selectively inhibit hGIIA signaling over catalysis, and x-ray crystal structures illustrate that signaling involves a pharmacologically distinct surface to the catalytic site. We demonstrate in rheumatoid fibroblast-like synoviocytes that non-catalytic signaling is associated with rapid internalization of the enzyme and colocalization with vimentin. Trafficking of exogenous hGIIA was monitored with immunofluorescence studies, which revealed that vimentin localization is disrupted by inhibitors of signaling that belong to a rare class of small molecule inhibitors that modulate protein-protein interactions. This study provides structural and pharmacological evidence for an association between vimentin, hGIIA, and arachidonic acid metabolism in synovial inflammation, avenues for selective interrogation of hGIIA signaling, and new strategies for therapeutic hGIIA inhibitor design.
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Affiliation(s)
- Lawrence K. Lee
- From the Faculty of Pharmacy, The University of Sydney, Sydney, New South Wales 2006, Australia
- School of Medical Sciences
| | | | - Romaric Bouveret
- St. Vincent's Hospital Clinical School, and
- Victor Chang Cardiac Research Institute, Sydney, New South Wales 2010, Australia
| | | | - Anthony P. Duff
- The Australian Nuclear Science and Technology Organisation, Sydney, New South Wales 2234, Australia
| | - Stephen J. Harrop
- School of Physics, Faculty of Science, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | | | - Richard P. Harvey
- St. Vincent's Hospital Clinical School, and
- Victor Chang Cardiac Research Institute, Sydney, New South Wales 2010, Australia
| | - Michael H. Gelb
- the Departments of Chemistry and Biochemistry, University of Washington, Seattle, Washington 98195
| | | | - Paul M. Curmi
- School of Physics, Faculty of Science, The University of New South Wales, Sydney, New South Wales 2052, Australia
- Centre for Applied Medical Research, St. Vincent's Hospital, Sydney, New South Wales 2010, Australia, and
| | | | - W. Bret Church
- From the Faculty of Pharmacy, The University of Sydney, Sydney, New South Wales 2006, Australia
- School of Medical Sciences
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Zeng F, Zou Z, Niu L, Li X, Teng M. AhV_aPA-induced vasoconstriction involves the IP₃Rs-mediated Ca²⁺ releasing. Toxicon 2013; 70:107-13. [PMID: 23648424 DOI: 10.1016/j.toxicon.2013.04.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 03/06/2013] [Accepted: 04/18/2013] [Indexed: 11/24/2022]
Abstract
AhV_aPA, the acidic PLA₂ purified from Agkistrodon halys pallas venom, was previously reported to possess a strong enzymatic activity and can remarkably induce a further contractile response on the 60 mM K⁺-induced contraction with an EC₅₀ in 369 nM on mouse thoracic aorta rings. In the present study, we found that the p-bromo-phenacyl-bromide (pBPB), which can completely inhibit the enzymatic activity of AhV_aPA, did not significantly reduce the contractile response on vessel rings induced by AhV_aPA, indicating that the vasoconstrictor effects of AhV_aPA are independent of the enzymatic activity. The inhibitor experiments showed that the contractile response induced by AhV_aPA is mainly attributed to the Ca²⁺ releasing from Ca²⁺ store, especially sarcoplasmic reticulum (SR). Detailed studies showed that the Ca²⁺ release from SR is related to the activation of inositol trisphosphate receptors (IP₃Rs) rather than ryanodine receptors (RyRs). Furthermore, the vasoconstrictor effect could be strongly reduced by pre-incubation with heparin, indicating that the basic amino acid residues on the surface of AhV_aPA may be involved in the interaction between AhV_aPA and the molecular receptors. These findings offer new insights into the functions of snake PLA₂ and provide a novel pathogenesis of A. halys pallas venom.
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Affiliation(s)
- Fuxing Zeng
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, PR China
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Huancahuire-Vega S, Corrêa DHA, Hollanda LM, Lancellotti M, Ramos CHI, Ponce-Soto LA, Marangoni S. Chemical modifications of PhTX-I myotoxin from Porthidium hyoprora snake venom: effects on structural, enzymatic, and pharmacological properties. BIOMED RESEARCH INTERNATIONAL 2012; 2013:103494. [PMID: 23484072 PMCID: PMC3591178 DOI: 10.1155/2013/103494] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 10/31/2012] [Indexed: 12/03/2022]
Abstract
We recently described the isolation of a basic PLA2 (PhTX-I) from Porthidium hyoprora snake venom. This toxin exhibits high catalytic activity, induces in vivo myotoxicity, moderates footpad edema, and causes in vitro neuromuscular blockade. Here, we describe the chemical modifications of specific amino acid residues (His, Tyr, Lys, and Trp), performed in PhTX-I, to study their effects on the structural, enzymatic, and pharmacological properties of this myotoxin. After chemical treatment, a single His, 4 Tyr, 7 Lys, and one Trp residues were modified. The secondary structure of the protein remained unchanged as measured by circular dichroism; however other results indicated the critical role played by Lys and Tyr residues in myotoxic, neurotoxic activities and mainly in the cytotoxicity displayed by PhTX-I. His residue and therefore catalytic activity of PhTX-I are relevant for edematogenic, neurotoxic, and myotoxic effects, but not for its cytotoxic activity. This dissociation observed between enzymatic activity and some pharmacological effects suggests that other molecular regions distinct from the catalytic site may also play a role in the toxic activities exerted by this myotoxin. Our observations supported the hypothesis that both the catalytic sites as the hypothetical pharmacological sites are relevant to the pharmacological profile of PhTX-I.
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Affiliation(s)
- Salomón Huancahuire-Vega
- Department of Biochemistry, Institute of Biology, State University of Campinas (UNICAMP), P.O. Box 6109, 13083-970 Campinas, SP, Brazil
| | - Daniel H. A. Corrêa
- Department of Organic Chemistry, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Luciana M. Hollanda
- Biotechnology Laboratory (LABIOTEC), Department of Biochemistry, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Marcelo Lancellotti
- Biotechnology Laboratory (LABIOTEC), Department of Biochemistry, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Carlos H. I. Ramos
- Department of Organic Chemistry, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, SP, Brazil
- National Institute of Science and Technology for Structural Biology and Bioimaging, Rio de Janeiro, RJ, Brazil
| | - Luis Alberto Ponce-Soto
- Department of Biochemistry, Institute of Biology, State University of Campinas (UNICAMP), P.O. Box 6109, 13083-970 Campinas, SP, Brazil
| | - Sergio Marangoni
- Department of Biochemistry, Institute of Biology, State University of Campinas (UNICAMP), P.O. Box 6109, 13083-970 Campinas, SP, Brazil
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Gohar GAN, Khattab SN, Farahat OO, Khalil HH. Kinetic studies of the reaction of phenacyl bromide derivatives with sulfur nucleophiles. J PHYS ORG CHEM 2011. [DOI: 10.1002/poc.1921] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Gamal Abdel-Nasser Gohar
- Department of Chemistry, Faculty of Science; Alexandria University; Ibrahimia 21321 Alexandria Egypt
- Faculty of Medical and Applied Sciences; Jazan University; Jazan Saudi Arabia
| | - Sherine Nabil Khattab
- Department of Chemistry, Faculty of Science; Alexandria University; Ibrahimia 21321 Alexandria Egypt
| | - Omaima Osman Farahat
- Department of Chemistry, Faculty of Science; Alexandria University; Ibrahimia 21321 Alexandria Egypt
| | - Hosam Hassan Khalil
- Department of Chemistry, Faculty of Science; Alexandria University; Ibrahimia 21321 Alexandria Egypt
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Cotrim CA, de Oliveira SCB, Diz Filho EB, Fonseca FV, Baldissera L, Antunes E, Ximenes RM, Monteiro HSA, Rabello MM, Hernandes MZ, de Oliveira Toyama D, Toyama MH. Quercetin as an inhibitor of snake venom secretory phospholipase A2. Chem Biol Interact 2011; 189:9-16. [DOI: 10.1016/j.cbi.2010.10.016] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 10/27/2010] [Accepted: 10/29/2010] [Indexed: 10/18/2022]
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13
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Marchi-Salvador DP, Fernandes CA, Silveira LB, Soares AM, Fontes MR. Crystal structure of a phospholipase A2 homolog complexed with p-bromophenacyl bromide reveals important structural changes associated with the inhibition of myotoxic activity. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2009; 1794:1583-90. [DOI: 10.1016/j.bbapap.2009.07.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Revised: 07/07/2009] [Accepted: 07/08/2009] [Indexed: 10/20/2022]
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Toyama DO, Marangoni S, Diz-Filho EBS, Oliveira SCB, Toyama MH. Effect of umbelliferone (7-hydroxycoumarin, 7-HOC) on the enzymatic, edematogenic and necrotic activities of secretory phospholipase A2 (sPLA2) isolated from Crotalus durissus collilineatus venom. Toxicon 2009; 53:417-26. [PMID: 19470355 DOI: 10.1016/j.toxicon.2008.12.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Revised: 12/11/2008] [Accepted: 12/23/2008] [Indexed: 11/15/2022]
Abstract
Flavonoids, coumarins and other polyphenolic compounds are powerful antioxidants both in hydrophilic and lipophylic environments with diverse pharmacological properties including anti-inflammatory activity. Despite being widely used as powerful therapeutic agents for blood coagulation disorders, more specifically to control some serine protease enzymes, the mechanism of anti-inflammatory activity of coumarins is unknown, unlike that of flavonoids. Although their controlling effect on serine proteases is well acknowledged, their action on secretory phospholipase A2 (sPLA2) remains obscure. The present study describes the interaction between umbelliferone (7-HOC) and the sPLA2 from Crotalus durissus collilineatus venom. In vitro inhibition of sPLA2 enzymatic activity by 7-HOC was estimated using 4N3OBA as substrate, resulting in an irreversible decrease in such activity proportional to 7-HOC concentration. The biophysical interaction between 7-HOC and sPLA2 was examined by fluorescent spectral analysis and circular dichroism studies. Results from both techniques clearly showed that 7-HOC strongly modified the secondary structure of this enzyme and CD spectra revealed that it strongly decreased sPLA2 alpha-helical conformation. In addition, two-dimensional electrophoresis indicated an evident difference between HPLC-purified native and 7-HOC-treated sPLA2s, which were used in pharmacological experiments to compare their biological activities. In vivo anti-inflammatory activity was assessed by the sPLA2-induced mouse paw edema model, in which 7-HOC presented an effect similar to those of dexamethasone and cyproheptadine against the pro-inflammatory effect induced by native sPLA2 on the mouse paw edema, mast cell degranulation and skin edema. On the other hand, 7-HOC exhibited a more potent inhibitory effect on sPLA2 than that of p-bromophenacyl bromide (p-BPB). Our data suggest that 7-HOC interacts with sPLA2 and causes some structural modifications that lead to a sharp decrease or inhibition of the edematogenic and myotoxic activities of this enzyme, indicating its potential use to suppress inflammation induced by sPLA2 from the snake venom.
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Affiliation(s)
- D O Toyama
- Centro de Cidncias Biológicas e da Saúde, Univesidade Mackenzie, São Paulo, Brazil
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15
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Catalytic activity-independent pathway is involved in phospholipase A2-induced apoptotic death of human leukemia U937 cells via Ca2+-mediated p38 MAPK activation and mitochondrial depolarization. Toxicol Lett 2009; 185:102-9. [DOI: 10.1016/j.toxlet.2008.12.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 11/11/2008] [Accepted: 12/04/2008] [Indexed: 11/17/2022]
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16
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Diz Filho E, Marangoni S, Toyama D, Fagundes F, Oliveira S, Fonseca F, Calgarotto A, Joazeiro P, Toyama M. Enzymatic and structural characterization of new PLA2 isoform isolated from white venom of Crotalus durissus ruruima. Toxicon 2009; 53:104-14. [DOI: 10.1016/j.toxicon.2008.10.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Revised: 10/12/2008] [Accepted: 10/22/2008] [Indexed: 12/01/2022]
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17
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Purification, characterization and bactericidal activities of basic phospholipase A2 from the venom of Agkistrodon halys (Chinese pallas). Biochimie 2008; 90:1372-88. [DOI: 10.1016/j.biochi.2008.04.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2007] [Accepted: 04/11/2008] [Indexed: 11/18/2022]
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18
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Chiou YL, Lin SR, Chang LS. Mutations onN-terminal region of Taiwan cobra phospholipase A2result in structurally distorted effects. J Pept Sci 2008; 14:890-7. [DOI: 10.1002/psc.1020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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19
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Chen KC, Kao PH, Lin SR, Chang LS. p38 MAPK activation and mitochondrial depolarization mediate the cytotoxicity of Taiwan cobra phospholipase A2 on human neuroblastoma SK-N-SH cells. Toxicol Lett 2008; 180:53-8. [PMID: 18582542 DOI: 10.1016/j.toxlet.2008.05.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2008] [Revised: 05/26/2008] [Accepted: 05/26/2008] [Indexed: 11/27/2022]
Abstract
Modification of catalytic residue His-47 with p-bromophenacyl bromide (BPB) abolished the enzymatic activity of Naja naja atra phospholipase A2 (PLA2). Additionally, alterations in the global structure and the spatial positions of Trp residues were noted in His-modified PLA2. The cell viability of human neuroblastoma SK-N-SH cells was decreased by approximately 40% and 20% after treatment with 10 microM PLA2 and BPB-PLA2, respectively. Native and His-modified PLA2 induced a necrotic cell death accompanied with an activation of p38 MAPK, the loss of mitochondrial membrane potential (DeltaPsim) and cytochrome c release. Pretreatment with SB202190 (p38 MAPK inhibitor) and cyclosporine A (inhibitor of mitochondria permeability transition pore) rescued cell viability, DeltaPsim and cytochrome c release of PLA2-treated cells. Taken together, our data indicate that PLA2 activity does not play an indispensable role on the cytotoxicity of N. naja atra PLA2, and suggest a novel function of secretory PLA2 in inducing cell death of neuroblastoma. Moreover, the reduced cytotoxicity noted with BPB-PLA2 may be partly attributed to conformational distortion after modification of His-47.
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Affiliation(s)
- Ku-Chung Chen
- Institute of Biomedical Sciences, National Sun Yat-Sen University-Kaohsiung Medical University Joint Research Center, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
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20
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Corrêa LC, Marchi-Salvador DP, Cintra AC, Sampaio SV, Soares AM, Fontes MR. Crystal structure of a myotoxic Asp49-phospholipase A2 with low catalytic activity: Insights into Ca2+-independent catalytic mechanism. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:591-9. [DOI: 10.1016/j.bbapap.2008.01.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2007] [Revised: 12/05/2007] [Accepted: 01/03/2008] [Indexed: 11/16/2022]
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21
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Kao PH, Chen KC, Lin SR, Chang LS. The structural and functional contribution ofN-terminal region and His-47 on Taiwan cobra phospholipase A2. J Pept Sci 2008; 14:342-8. [DOI: 10.1002/psc.943] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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22
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Chennubhotla C, Bahar I. Signal propagation in proteins and relation to equilibrium fluctuations. PLoS Comput Biol 2007; 3:1716-26. [PMID: 17892319 PMCID: PMC1988854 DOI: 10.1371/journal.pcbi.0030172] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Accepted: 07/20/2007] [Indexed: 11/19/2022] Open
Abstract
Elastic network (EN) models have been widely used in recent years for describing protein dynamics, based on the premise that the motions naturally accessible to native structures are relevant to biological function. We posit that equilibrium motions also determine communication mechanisms inherent to the network architecture. To this end, we explore the stochastics of a discrete-time, discrete-state Markov process of information transfer across the network of residues. We measure the communication abilities of residue pairs in terms of hit and commute times, i.e., the number of steps it takes on an average to send and receive signals. Functionally active residues are found to possess enhanced communication propensities, evidenced by their short hit times. Furthermore, secondary structural elements emerge as efficient mediators of communication. The present findings provide us with insights on the topological basis of communication in proteins and design principles for efficient signal transduction. While hit/commute times are information-theoretic concepts, a central contribution of this work is to rigorously show that they have physical origins directly relevant to the equilibrium fluctuations of residues predicted by EN models.
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Affiliation(s)
- Chakra Chennubhotla
- Department of Computational Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Ivet Bahar
- Department of Computational Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
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23
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Sacquin-Mora S, Laforet E, Lavery R. Locating the active sites of enzymes using mechanical properties. Proteins 2007; 67:350-9. [PMID: 17311346 DOI: 10.1002/prot.21353] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We have applied the calculation of mechanical properties to a dataset of almost 100 enzymes to determine the extent to which catalytic residues have distinct properties. Specifically, we have calculated force constants describing the ease of moving any given amino acid residue with respect to the other residues in the protein. The results show that catalytic residues are invariably associated with high force constants. Choosing an appropriate cutoff enables the detection of roughly 80% of catalytic residues with only 25% of false positives. It is shown that neither multidomain structures, nor the presence or absence of bound ligands hinder successful detections. It is however noted that active sites near the protein surface are more difficult to detect and that non-catalytic, but structurally key residues may also exhibit high force constants.
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Affiliation(s)
- Sophie Sacquin-Mora
- Laboratoire de Biochimie Théorique, CNRS UPR 9080, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
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24
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Rouault M, Rash LD, Escoubas P, Boilard E, Bollinger J, Lomonte B, Maurin T, Guillaume C, Canaan S, Deregnaucourt C, Schrével J, Doglio A, Gutiérrez JM, Lazdunski M, Gelb MH, Lambeau G. Neurotoxicity and other pharmacological activities of the snake venom phospholipase A2 OS2: the N-terminal region is more important than enzymatic activity. Biochemistry 2006; 45:5800-16. [PMID: 16669624 PMCID: PMC2796912 DOI: 10.1021/bi060217r] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Several snake venom secreted phospholipases A2 (sPLA2s) including OS2 exert a variety of pharmacological effects ranging from central neurotoxicity to anti-HIV activity by mechanisms that are not yet fully understood. To conclusively address the role of enzymatic activity and map the key structural elements of OS2 responsible for its pharmacological properties, we have prepared single point OS2 mutants at the catalytic site and large chimeras between OS2 and OS1, a homologous but nontoxic sPLA2. Most importantly, we found that the enzymatic activity of the active site mutant H48Q is 500-fold lower than that of the wild-type protein, while central neurotoxicity is only 16-fold lower, providing convincing evidence that catalytic activity is at most a minor factor that determines central neurotoxicity. The chimera approach has identified the N-terminal region (residues 1-22) of OS2, but not the central one (residues 58-89), as crucial for both enzymatic activity and pharmacological effects. The C-terminal region of OS2 (residues 102-119) was found to be critical for enzymatic activity, but not for central neurotoxicity and anti-HIV activity, allowing us to further dissociate enzymatic activity and pharmacological effects. Finally, direct binding studies with the C-terminal chimera, which poorly binds to phospholipids while it is still neurotoxic, led to the identification of a subset of brain N-type receptors which may be directly involved in central neurotoxicity.
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Affiliation(s)
- Morgane Rouault
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
| | - Lachlan D. Rash
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
| | - Pierre Escoubas
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
| | - Eric Boilard
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
| | - James Bollinger
- Departments of Chemistry and Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - Bruno Lomonte
- Universidad de Costa Rica, Faculdad de Microbiologia, Instituto Clodomiro Picado, San José, Costa Rica
| | - Thomas Maurin
- Laboratoire de Virologie, IFR50, Faculté de Médecine, 06107 Nice cedex 2, France
| | - Carole Guillaume
- USM 0504, Biologie Fonctionnelle des Protozoaires, Laboratoire de Biologie Parasitaire, Museum National d’Histoire Naturelle, 61 rue Buffon, 75231 Paris cedex 05, France
| | - Stéphane Canaan
- Laboratoire d'Enzymologie Interfaciale et de Physiologie de la Lipolyse, CNRS-UPR 9025, 31 Chemin Joseph-Aiguier, 13402 Marseille cedex 20, France
| | - Christiane Deregnaucourt
- USM 0504, Biologie Fonctionnelle des Protozoaires, Laboratoire de Biologie Parasitaire, Museum National d’Histoire Naturelle, 61 rue Buffon, 75231 Paris cedex 05, France
| | - Joseph Schrével
- USM 0504, Biologie Fonctionnelle des Protozoaires, Laboratoire de Biologie Parasitaire, Museum National d’Histoire Naturelle, 61 rue Buffon, 75231 Paris cedex 05, France
| | - Alain Doglio
- Laboratoire de Virologie, IFR50, Faculté de Médecine, 06107 Nice cedex 2, France
| | - José María Gutiérrez
- Universidad de Costa Rica, Faculdad de Microbiologia, Instituto Clodomiro Picado, San José, Costa Rica
| | - Michel Lazdunski
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
| | - Michael H. Gelb
- Departments of Chemistry and Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - Gérard Lambeau
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
- Address correspondence to: Gérard Lambeau, Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-UMR 6097, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France, Tel. +33 (0) 4 93 95 77 33; Fax. +33 (0) 4 93 95 77 08;
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25
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Shashidharamurthy R, Kemparaju K. A neurotoxic phospholipase A2 variant: Isolation and characterization from eastern regional Indian cobra (Naja naja) venom. Toxicon 2006; 47:727-33. [PMID: 16574178 DOI: 10.1016/j.toxicon.2006.01.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 01/12/2006] [Accepted: 01/12/2006] [Indexed: 10/24/2022]
Abstract
CM-Sephadex C-25 column chromatography profile of Indian cobra (Naja naja) venom from eastern region showed a distinct and a dominant phospholipase peak, peak-10, while it was not seen in either southern or western venom samples. Peak-10 was subjected to CM-Sephadex C-25 and Sephadex G-50 column chromatography to isolate NN-X-PLA(2). NN-X-PLA(2) is a single chain protein with the relative molecular weight of 10kDa by SDS-PAGE. It was toxic to mice with an LD(50) value 0.098 mg/kg body weight (i.p.) and the mice exhibited acute neurotoxic symptoms. Upon indirect stimulation, it inhibited the twitching of frog's gastrocnemius muscle in a dose dependent manner. NN-X-PLA(2) was weakly anticoagulant and devoid of cytotoxicity, myotoxicity, hemorrhage, edema inducing, and directlytic activities and effects on platelet aggregation process. Upon chemical modification independently with p-bromophenacyl bromide and acetic anhydride, NN-X-PLA(2) lost both enzymatic and toxic properties.
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Affiliation(s)
- R Shashidharamurthy
- Department of Biochemistry, University of Mysore, Mnasagangotri, Mysore 570 006, India
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26
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Singh N, Jabeen T, Pal A, Sharma S, Perbandt M, Betzel C, Singh TP. Crystal structures of the complexes of a group IIA phospholipase A2with two natural anti‐inflammatory agents, anisic acid, and atropine reveal a similar mode of binding. Proteins 2006; 64:89-100. [PMID: 16596639 DOI: 10.1002/prot.20970] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Secretory low molecular weight phospholipase A(2)s (PLA(2)s) are believed to be involved in the release of arachidonic acid, a precursor for the biosynthesis of pro-inflammatory eicosanoids. Therefore, the specific inhibitors of these enzymes may act as potent anti-inflammatory agents. Similarly, the compounds with known anti-inflammatory properties should act as specific inhibitors. Two plant compounds, (a) anisic acid (4-methoxy benzoic acid) and (b) atropine (8-methyl-8-azabicyclo oct-3-hydroxy-2-phenylpropanoate), have been used in various inflammatory disorders. Both compounds (a) and (b) have been found to inhibit PLA(2) activity having binding constants of 4.5 x 10(-5) M and 2.1 x 10(-8) M, respectively. A group IIA PLA(2) was isolated and purified from the venom of Daboia russelli pulchella (DRP) and its complexes were made with anisic acid and atropine. The crystal structures of the two complexes (i) and (ii) of PLA(2) with compounds (a) and (b) have been determined at 1.3 and 1.2 A resolutions, respectively. The high-quality observed electron densities for the two compounds allowed the accurate determinations of their atomic positions. The structures revealed that these compounds bound to the enzyme at the substrate - binding cleft and their positions were stabilized by networks of hydrogen bonds and hydrophobic interactions. The most characteristic interactions involving Asp 49 and His 48 were clearly observed in both complexes, although the residues that formed hydrophobic interactions with these compounds were not identical because their positions did not exactly superimpose in the large substrate-binding hydrophobic channel. Owing to a relatively small size, the structure of anisic acid did not alter upon binding to PLA(2), while that of atropine changed significantly when compared with its native crystal structure. The conformation of the protein also did not show notable changes upon the bindings of these ligands. The mode of binding of anisic acid to the present group II PLA(2) is almost identical to its binding with bovine pancreatic PLA(2) of group I. On the other hand, the binding of atropine to PLA(2) is similar to that of another plant alkaloid aristolochic acid.
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Affiliation(s)
- Nagendra Singh
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India
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27
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Iglesias CV, Aparicio R, Rodrigues-Simioni L, Camargo EA, Antunes E, Marangoni S, de Oliveira Toyama D, Beriam LOS, Monteiro HSA, Toyama MH. Effects of morin on snake venom phospholipase A2 (PLA2). Toxicon 2005; 46:751-8. [PMID: 16185736 DOI: 10.1016/j.toxicon.2005.07.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Accepted: 07/22/2005] [Indexed: 11/26/2022]
Abstract
Flavonoids are potent anti-inflammatory compounds isolated from several plant extracts, and have been used experimentally against inflammatory processes. In this work, a PLA2 isolated from the Crotalus durissus cascavella venom and rat paw oedema were used as a model to study the effect of flavonoids on PLA2. We observed that a treatment of PLA2 with morin induces several modifications in the aromatic amino acids, with accompanying changes in its amino acid composition. In addition, results from circular dichroism spectroscopy and UV scanning revealed important structural modifications. Concomitantly, a considerable decrease in the enzymatic and antibacterial activities was observed, even though anti-inflammatory and neurotoxic activities were not affected. These apparent controversial results may be an indication that PLA2 possess a second pharmacological site which does not affect or depend on the enzymatic activity.
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28
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Barbosa PSF, Martins AMC, Havt A, Toyama DO, Evangelista JSAM, Ferreira DPP, Joazeiro PP, Beriam LOS, Toyama MH, Fonteles MC, Monteiro HSA. Renal and antibacterial effects induced by myotoxin I and II isolated from Bothrops jararacussu venom. Toxicon 2005; 46:376-86. [PMID: 16115661 DOI: 10.1016/j.toxicon.2005.04.024] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2004] [Revised: 04/19/2005] [Accepted: 04/22/2005] [Indexed: 11/19/2022]
Abstract
Bothrops jararacussu myotoxin I (BthTx-I; Lys 49) and II (BthTX-II; Asp 49) were purified by ion-exchange chromatography and reverse phase HPLC. In this work we used the isolated perfused rat kidney method to evaluate the renal effects of B. jararacussu myotoxins I (Lys49 PLA2) and II (Asp49 PLA2) and their possible blockage by indomethacin. BthTX-I (5 microg/ml) and BthTX-II (5 microg/ml) increased perfusion pressure (PP; ct120=110.28+/-3.70 mmHg; BthTX I=171.28+/-6.30*mmHg; BthTX II=175.50+/-7.20*mmHg), renal vascular resistance (RVR; ct120=5.49+/-0.54 mmHg/ml.g(-1)min(-1); BthTX I=8.62+/-0.37*mmHg/ml g(-1)min(-1); BthTX II=8.9+/-0.36*mmHg/ml g(-1)min(-1)), urinary flow (UF; ct(120)=0.14+/-0.01ml g(-1)min(-1); BthTX I=0.32+/-0.05*ml g(-1)min(-1); BthTX II=0.37+/-0.01*ml g(-1)min(-1)) and glomerular filtration rate (GFR; ct120=0.72+/-0.10 ml g(-1)min(-1); BthTX I=0.85+/-0.13*ml g(-1)min(-1); BthTX II=1.22+/-0.28*ml g(-1)min(-1)). In contrast decreased the percent of sodium tubular transport (%TNa(+); ct(120)=79,76+/-0.56; BthTX I=62.23+/-4.12*; BthTX II=70.96+/-2.93*) and percent of potassium tubular transport (%TK(+);ct120=66.80+/-3.69; BthTX I=55.76+/-5.57*; BthTX II=50.86+/-6.16*). Indomethacin antagonized the vascular, glomerular and tubular effects promoted by BthTX I and it's partially blocked the effects of BthTX II. In this work also evaluated the antibacterial effects of BthTx-I and BthTx-II against Xanthomonas axonopodis. pv. passiflorae (Gram-negative bacteria) and we observed that both PLA2 showed antibacterial activity. Also we observed that proteins Also we observed that proteins chemically modified with 4-bromophenacyl bromide (rho-BPB) decrease significantly the antibacterial effect of both PLA2. In conclusion, BthTx I and BthTX II caused renal alteration and presented activity antimicrobial. The indomethacin was able to antagonize totally the renal effects induced by BthTx I and partially the effects promoted by BthTx II, suggesting involvement of inflammatory mediators in the renal effects caused by myotoxins. In the other hand, other effects could be independently of the enzymatic activity of the BthTX II and the C-terminal domain could be involved in both effects promoted for PLA2.
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Affiliation(s)
- P S F Barbosa
- Institute of Biomedicine and Clinical Research Unit, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil
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29
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Yang LW, Bahar I. Coupling between catalytic site and collective dynamics: a requirement for mechanochemical activity of enzymes. Structure 2005; 13:893-904. [PMID: 15939021 PMCID: PMC1489920 DOI: 10.1016/j.str.2005.03.015] [Citation(s) in RCA: 204] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2005] [Revised: 03/23/2005] [Accepted: 03/23/2005] [Indexed: 12/31/2022]
Abstract
Growing evidence supports the view that enzymatic activity results from a subtle interplay between chemical kinetics and molecular motions. A systematic analysis is performed here to delineate the type and level of coupling between catalysis and conformational mechanics. The dynamics of a set of 98 enzymes representative of different EC classes are analyzed with the Gaussian network model (GNM) and compared with experimental data. In more than 70% of the examined enzymes, the global hinge centers predicted by the GNM are found to be colocalized with the catalytic sites experimentally identified. Low translational mobility (< 7%) is observed for the catalytic residues, consistent with the fine-tuned design of enzymes to achieve precise mechanochemical activities. Ligand binding sites, while closely neighboring catalytic sites, enjoy a moderate flexibility to accommodate the ligand binding. These findings could serve as additional criteria for assessing drug binding residues and could lessen the computational burden of substrate docking searches.
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Affiliation(s)
- Lee-Wei Yang
- Department of Computational Biology, school of Medicine, University of Pittsburgh, Pennsylvania 15261, USA
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30
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Yang LW, Liu X, Jursa CJ, Holliman M, Rader AJ, Karimi HA, Bahar I. iGNM: a database of protein functional motions based on Gaussian Network Model. Bioinformatics 2005; 21:2978-87. [PMID: 15860562 PMCID: PMC1752228 DOI: 10.1093/bioinformatics/bti469] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
MOTIVATION The knowledge of protein structure is not sufficient for understanding and controlling its function. Function is a dynamic property. Although protein structural information has been rapidly accumulating in databases, little effort has been invested to date toward systematically characterizing protein dynamics. The recent success of analytical methods based on elastic network models, and in particular the Gaussian Network Model (GNM), permits us to perform a high-throughput analysis of the collective dynamics of proteins. RESULTS We computed the GNM dynamics for 20 058 structures from the Protein Data Bank, and generated information on the equilibrium dynamics at the level of individual residues. The results are stored on a web-based system called iGNM and configured so as to permit the users to visualize or download the results through a standard web browser using a simple search engine. Static and animated images for describing the conformational mobility of proteins over a broad range of normal modes are accessible, along with an online calculation engine available for newly deposited structures. A case study of the dynamics of 20 non-homologous hydrolases is presented to illustrate the utility of the iGNM database for identifying key residues that control the cooperative motions and revealing the connection between collective dynamics and catalytic activity.
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Affiliation(s)
- Lee-Wei Yang
- Department of Computational Biology, School of Medicine, University of Pittsburgh Pittsburgh, PA 15213, USA.
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31
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Fuly AL, Soares AM, Marcussi S, Giglio JR, Guimarães JA. Signal transduction pathways involved in the platelet aggregation induced by a D-49 phospholipase A2 isolated from Bothrops jararacussu snake venom. Biochimie 2005; 86:731-9. [PMID: 15556284 DOI: 10.1016/j.biochi.2004.07.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2003] [Revised: 07/01/2004] [Accepted: 07/02/2004] [Indexed: 10/26/2022]
Abstract
Bothropstoxin-II (Bthtx-II), an Asp-49 phospholipase A(2) (D-PLA(2)) isolated from Bothrops jararacussu snake venom is able to induce platelet aggregation in a concentration-dependent manner. This effect was not due to the release of ADP from platelets since the aggregation was not suppressed by ADP scavenger systems. PMSF and PPACK were unable to inhibit Bthtx-II-induced platelet aggregation. Thus, a thrombin-like proaggregating activity of Bthtx-II can be excluded as its mechanism of action. On the other hand, indomethacin at low concentrations inhibited more markedly the ATP-release reaction than the aggregation induced by Bthtx-II, indicating that generation of cyclooxigenase products is not the most important event for the platelet aggregation reaction. It was also found that staurosporine and genistein suppressed both platelet aggregation and ATP-release reactions, but not the platelet shape-change induced by Bthtx-II. Substances that either directly activates adenylyl cyclase enzyme (forskolin and PGE(1)) or cell-permeant increasing agents (dibutyril-cAMP) inhibited in a concentration-dependent fashion, the platelet aggregation effects induced by the protein. It is concluded that Bthtx-II induces platelet aggregation and secretion through multiple signal transduction pathways.
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Affiliation(s)
- André L Fuly
- Departamento de Bioquímica Médica, ICB/CCS, Universidade Federal do Rio de Janeiro, 21941-590 Brazil
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32
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Magro AJ, Murakami MT, Marcussi S, Soares AM, Arni RK, Fontes MRM. Crystal structure of an acidic platelet aggregation inhibitor and hypotensive phospholipase A2 in the monomeric and dimeric states: insights into its oligomeric state. Biochem Biophys Res Commun 2004; 323:24-31. [PMID: 15351695 DOI: 10.1016/j.bbrc.2004.08.046] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2004] [Indexed: 11/18/2022]
Abstract
Phospholipases A2 belong to the superfamily of proteins which hydrolyzes the sn-2 acyl groups of membrane phospholipids to release arachidonic acid and lysophospholipids. An acidic phospholipase A2 isolated from Bothrops jararacussu snake venom presents a high catalytic, platelet aggregation inhibition and hypotensive activities. This protein was crystallized in two oligomeric states: monomeric and dimeric. The crystal structures were solved at 1.79 and 1.90 angstroms resolution, respectively, for the two states. It was identified a Na+ ion at the center of Ca2+-binding site of the monomeric form. A novel dimeric conformation with the active sites exposed to the solvent was observed. Conformational states of the molecule may be due to the physicochemical conditions used in the crystallization experiments. We suggest dimeric state is one found in vivo.
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Affiliation(s)
- Angelo J Magro
- Departamento de Física e Biofísica, Instituto de Biociências, UNESP, Botucatu-SP, Brazil
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33
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Takeda AAS, dos Santos JI, Marcussi S, Silveira LB, Soares AM, Fontes MRM. Crystallization and preliminary X-ray diffraction analysis of an acidic phospholipase A(2) complexed with p-bromophenacyl bromide and alpha-tocopherol inhibitors at 1.9- and 1.45-A resolution. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2004; 1699:281-4. [PMID: 15158738 DOI: 10.1016/j.bbapap.2004.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2003] [Revised: 02/10/2004] [Accepted: 02/11/2004] [Indexed: 11/29/2022]
Abstract
An acidic phospholipase A(2) (PLA(2)) isolated from Bothrops jararacussu snake venom was crystallized with two inhibitors: alpha-tocopherol (vitamin E) and p-bromophenacyl bromide (BPB). The crystals diffracted at 1.45- and 1.85-A resolution, respectively, for the complexes with alpha-tocopherol and p-bromophenacyl bromide. The crystals are not isomorphous with those of the native protein, suggesting the inhibitors binding was successful and changes in the quaternary structure may have occurred.
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Affiliation(s)
- Agnes A S Takeda
- Departamento de Física e Biofísica, Instituto de Biociências, UNESP, Dist. Rubiao Jr. s/n-C.P. 510, CEP 18618-000, Botucatu-São Paulo, Brazil
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Soares AM, Giglio JR. Chemical modifications of phospholipases A2 from snake venoms: effects on catalytic and pharmacological properties. Toxicon 2004; 42:855-68. [PMID: 15019487 DOI: 10.1016/j.toxicon.2003.11.004] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phospholipases A2 (PLA2s) constitute major components of snake venoms and have been extensively investigated not only because they are very abundant in these venoms but mainly because they display a wide range of biological effects, including neurotoxic, myotoxic, cytotoxic, edema-inducing, artificial membrane disrupting, anti-coagulant, platelet aggregation inhibiting, hypotensive, bactericidal, anti-HIV, anti-tumoral, anti-malarial and anti-parasitic. Due to this functional diversity, these structurally similar proteins aroused the interest of many researchers as molecular models for study of structure-function relationships. One of the main experimental strategies used for the study of myotoxic PLA2s is the traditional chemical modification of specific amino acid residues (His, Met, Lys, Tyr, Trp and others) and examination of the consequent effects upon the enzymatic, toxic and pharmacological activities. This line of research has provided useful insights into the structural determinants of the action of these enzymes and, together with additional strategies, supports the concept of the presence of 'pharmacological sites' distinct from the catalytic site in snake venom myotoxic PLA2s.
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Affiliation(s)
- Andreimar M Soares
- Departamento de Biotecnologia, Universidade de Ribeirão Preto (UNAERP), Ribeirão Presto, SP, Brazil.
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35
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Soares AM, Sestito WP, Marcussi S, Stábeli RG, Andrião-Escarso SH, Cunha OAB, Vieira CA, Giglio JR. Alkylation of myotoxic phospholipases A2 in Bothrops moojeni venom: a promising approach to an enhanced antivenom production. Int J Biochem Cell Biol 2004; 36:258-70. [PMID: 14643891 DOI: 10.1016/s1357-2725(03)00237-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Bothrops moojeni crude venom (MjCV) and its two major toxins, namely myotoxin I (MjTX-I) and myotoxin II (MjTX-II) were alkylated by p-bromophenacyl bromide (BPB). After alkylation the i.p. LD(50) (mice) of MjCV and MjTX-I/II increased from 6.0 to 15.7mg/kg and from 8.0 to 45.0mg/kg, respectively. In addition, doses of 5x LD(50) of alkylated MjTX-I did not cause a single death in mice and no myonecrosis was detected for the alkylated toxins, although both proteins still induced edema. Antibodies to native and modified crude venom or myotoxins cross-reacted with 12 purified class II myotoxic phospholipases A(2) found in snake venoms of the genus Bothrops. Myotoxic PLA(2)s from class I and class III were not recognized by the above antibodies. These results suggest that the overall antigenic structure is conserved among class II myotoxic PLA(2)s, despite differences in their amino acid sequences. Anti-MjTX-I-BPB and anti-MjTX-II-BPB rabbit serum, obtained against the modified myotoxins, were apparently more efficient than those obtained against the native myotoxins. In neutralization experiments, pre-incubation of crude venom or isolated myotoxins with antibodies raised against the native or modified toxins inhibited their PLA(2) and myotoxic activities. Therefore, alkylation of His48 by BPB strongly reduces the local tissue damage induced by B. moojeni venom or isolated myotoxins while retaining antigenicity, which suggests a promising procedure for an enhanced antiophidian serum production for practical purposes.
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Affiliation(s)
- Andreimar M Soares
- Departamento de Biotecnologia, Universidade de Ribeirão Preto, UNAERP, SP, Ribeirão Preto, Brazil
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Murakami MT, Arni RK. A structure based model for liposome disruption and the role of catalytic activity in myotoxic phospholipase A2s. Toxicon 2003; 42:903-13. [PMID: 15019490 DOI: 10.1016/j.toxicon.2003.11.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Venom phospholipase A2s (PLA2s) display a wide spectrum of pharmacological activities and, based on the wealth of biochemical and structural data currently available for PLA2s, mechanistic models can now be inferred to account for some of these activities. A structural model is presented for the role played by the distribution of surface electrostatic potential in the ability of myotoxic D49/K49 PLA2s to disrupt multilamellar vesicles containing negatively charged natural and non-hydrolyzable phospholipids. Structural evidence is provided for the ability of K49 PLA2s to bind phospholipid analogues and for the existence of catalytic activity in K49 PLA2s. The importance of the existence of catalytic activity of D49 and K49 PLA2s in myotoxicity is presented.
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Affiliation(s)
- M T Murakami
- Department of Biophysics, IBILCE/UNESP, R. Cristovão Colombo 2265, CEP 15054-000, São José do Rio Preto-SP, Brazil
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Fuly AL, Calil-Elias S, Martinez AMB, Melo PA, Guimarães JA. Myotoxicity induced by an acidic Asp-49 phospholipase A(2) isolated from Lachesis muta snake venom. Comparison with lysophosphatidylcholine. Int J Biochem Cell Biol 2003; 35:1470-81. [PMID: 12818242 DOI: 10.1016/s1357-2725(03)00129-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In a previous report we showed that Lachesis muta crude venom displays potent indirect hemolytic activity and myotoxicity when injected into mice. Then, a phospholipase A(2) (PLA(2)) (LM-PLA(2)-I) responsible for these activities was isolated. More recently, a catalytically active isoenzyme (LM-PLA(2)-II) with molecular mass of 18 kDa and isoeletric point at pH 5.4 was isolated from the same snake venom. LM-PLA(2)-II inhibited ADP- and collagen-induced platelet aggregation as well as induced a potent paw edema reaction in rats. Here we show that LM-PLA(2)-II induced myotoxic effects both in vitro characterized by an increase on the rate of creatine kinase (CK) release from isolated mice extensor digitorum longus (EDL) muscles and in vivo by increasing plasma CK activity of injected mice. Histological analysis showed an intense damage in muscle cells injected with LM-PLA(2)-II. It was also shown that exogenous lysophosphatidylcholine (lyso-pc) behaved as a typical myotoxin damaging muscle cells, producing myonecrosis characterized by local infiltration of inflammatory cells similarly to that observed for LM-PLA(2)-II. Hemorrhage and lethal effects were not observed neither with LM-PLA(2)-II nor lyso-pc. As previously observed for other biological activities, pretreatment of LM-PLA(2)-II with p-bromophenacyl bromide (p-BPB) or acetic anhydride abolished all the enzyme's actions. The data confirms that biological activities displayed by LM-PLA(2)-II, including the myotoxic effects reported here, are all dependent on its enzymatic activity where the product formed (lyso-pc) may play an important function on such myotoxicity.
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Affiliation(s)
- André L Fuly
- Departamento de Bioquímica Médica, Universidade Federal do Rio de Janeiro, RJ, Rio de Janeiro, Brazil
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Tatulian SA. Structural effects of covalent inhibition of phospholipase A2 suggest allosteric coupling between membrane binding and catalytic sites. Biophys J 2003; 84:1773-83. [PMID: 12609879 PMCID: PMC1302746 DOI: 10.1016/s0006-3495(03)74985-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Phospholipase A(2) (PLA(2)) binds to membranes and catalyzes phospholipid hydrolysis, thus initiating the biosynthesis of lipid-derived mediators of inflammation. A snake-venom PLA(2) was completely inhibited by covalent modification of the catalytic histidine 48 by p-bromophenacyl bromide. Moreover, His(48) modification affected PLA(2) structure, its membrane-binding affinity, and the effects of PLA(2) on the membrane structure. The native PLA(2) increased the order parameter of fluid membranes, whereas the opposite effect was observed for gel-state membranes. The data suggest membrane dehydration by PLA(2) and the formation of PLA(2)-membrane hydrogen bonding. The inhibited PLA(2) had lower membrane-binding affinity and exerted weaker effects on membrane hydration and on the lipid-order parameter. Although membrane binding resulted in formation of more flexible alpha-helices in the native PLA(2), which corresponds to faster amide hydrogen exchange, the modified enzyme was more resistant to hydrogen exchange and experienced little structural change upon membrane binding. The data suggest that 1), modification of a catalytic residue of PLA(2) induces conformational changes that propagate to the membrane-binding surface through an allosteric mechanism; 2), the native PLA(2) acquires more dynamic properties during interfacial activation via membrane binding; and 3), the global conformation of the inhibited PLA(2), including the alpha-helices, is less stable and is not influenced by membrane binding. These findings provide further evidence for an allosteric coupling between the membrane-binding (regulatory) site and the catalytic center of PLA(2), which contributes to the interfacial activation of the enzyme.
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Affiliation(s)
- Suren A Tatulian
- Biomolecular Science Center and Department of Molecular Biology and Microbiology, University of Central Florida, Orlando 32826, USA.
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39
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Andrião-Escarso SH, Soares AM, Fontes MRM, Fuly AL, Corrêa FMA, Rosa JC, Greene LJ, Giglio JR. Structural and functional characterization of an acidic platelet aggregation inhibitor and hypotensive phospholipase A(2) from Bothrops jararacussu snake venom. Biochem Pharmacol 2002; 64:723-32. [PMID: 12167491 DOI: 10.1016/s0006-2952(02)01210-8] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
An acidic (pI approximately 4.5) phospholipase A(2) (BthA-I-PLA(2)) was isolated from Bothrops jararacussu snake venom by ion-exchange chromatography on a CM-Sepharose column followed by reverse phase chromatography on an RP-HPLC C-18 column. It is an approximately 13.7kDa single chain Asp49 PLA(2) with approximately 122 amino acid residues, 7 disulfide bridges, and the following N-terminal sequence: 1SLWQFGKMINYVM-GESGVLQYLSYGCYCGLGGQGQPTDATDRCCFVHDCC(51). Crystals of this acidic protein diffracted beyond 2.0A resolution. These crystals are monoclinic and have unit cell dimensions of a=33.9, b=63.8, c=49.1A, and beta=104.0 degrees. Although not myotoxic, cytotoxic, or lethal, the protein was catalytically 3-4 times more active than BthTX-II, a basic D49 myotoxic PLA(2) from the same venom and other Bothrops venoms. Although it showed no toxic activity, it was able to induce time-independent edema, this activity being inhibited by EDTA. In addition, BthA-I-PLA(2) caused a hypotensive response in the rat and inhibited platelet aggregation. Catalytic, antiplatelet and other activities were abolished by chemical modification with 4-bromophenacyl bromide, which is known to covalently bind to His48 of the catalytic site. Antibodies raised against crude B. jararacussu venom recognized this acidic PLA(2), while anti-Asp49-BthTX-II recognized it weakly and anti-Lys49-BthTX-I showed the least cross-reaction. These data confirm that myotoxicity does not necessarily correlate with catalytic activity in native PLA(2) homologues and that either of these two activities may exist alone. BthA-I-PLA(2), in addition to representing a relevant molecular model of catalytic activity, is also a promising hypotensive agent and platelet aggregation inhibitor for further studies.
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Affiliation(s)
- Sílvia H Andrião-Escarso
- Departamento de Bioquímica e Imunologia, FMRP, Universidade de São Paulo, 14049-900 Ribeirão Preto-SP, Brazil
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40
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Soares AM, Mancin AC, Cecchini AL, Arantes EC, França SC, Gutiérrez JM, Giglio JR. Effects of chemical modifications of crotoxin B, the phospholipase A(2) subunit of crotoxin from Crotalus durissus terrificus snake venom, on its enzymatic and pharmacological activities. Int J Biochem Cell Biol 2001; 33:877-88. [PMID: 11461830 DOI: 10.1016/s1357-2725(01)00065-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Crotoxin B, the basic Asp49-PLA(2) subunit from crotoxin, the main component of Crotalus durissus terrificus venom, displays myotoxic, edema-inducing, bactericidal (upon Escherichia coli), liposomal-disrupting and anticoagulant activities. Chemical modifications of His (with 4-bromophenacyl bromide, BPB), Tyr (with 2-nitrobenzenesulphonyl fluoride, NBSF), Trp (with o-nitrophenylsulphenyl chloride, NPSC) and Lys (with acetic anhydride) residues of this protein, in addition to cleavage with cyanogen bromide (CNBr) and inhibition with ethylenediaminetetraacetic acid (EDTA), were carried out in order to study their effects on enzymatic and pharmacological activities. Lethality was reduced after modification of His or Lys residues, as well as after cleavage with CNBr, while enzymatic activity was completely abolished after modification of His or incubation with EDTA. Modification of Lys or Tyr, or cleavage with CNBr, partially reduced enzymatic activity. Anticoagulant activity was modified similarly to enzymatic activity, evidencing the dependency of this pharmacological effect on catalytic activity. Myotoxicity was reduced after modification of His or Lys, as well as after cleavage with CNBr, whereas EDTA reduced this effect to a lesser extent. Bactericidal effect was significantly reduced only after modification of Lys and after cleavage with CNBr. Edema-inducing activity was partially inhibited after treatment with EDTA and strongly reduced after acetylation of Lys residues and cleavage with CNBr, being only partially reduced after His alkylation. On the other hand, liposome disrupting activity was only partially reduced after modification of His and Tyr or after cleavage with CNBr. Modification of Trp residue partially reduced lethality and myotoxicity but did not affect enzymatic or anticoagulant activities. These data indicate that enzymatic activity is relevant for some pharmacological effects induced by crotoxin B (mainly lethal, myotoxic and anticoagulant activities), and also evidence that this subunit of crotoxin displays regions different from the active catalytic site which are involved in some of the toxic and pharmacological effects induced by this phospholipase A(2).
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Affiliation(s)
- A M Soares
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina, Universidade de São Paulo, USP 14049-900, Ribeirão Preto SP, Brazil
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41
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Soares AM, Andrião-Escarso SH, Bortoleto RK, Rodrigues-Simioni L, Arni RK, Ward RJ, Gutiérrez JM, Giglio JR. Dissociation of Enzymatic and Pharmacological Properties of Piratoxins-I and -III, Two Myotoxic Phospholipases A2 from Bothrops pirajai Snake Venom. Arch Biochem Biophys 2001; 387:188-96. [PMID: 11370840 DOI: 10.1006/abbi.2000.2244] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Piratoxins (PrTX) I and III are phospholipases A2 (PLA2s) or PLA2 homologue myotoxins isolated from Bothrops pirajai snake venom, which also induce myonecrosis, bactericidal activity against Escherichia coli, disruption of artificial membranes, and edema. PrTX-III is a catalytically active hemolytic and anticoagulant Asp49 PLA2, while PrTX-I is a Lys49 PLA2 homologue, which is catalytically inactive on artificial substrates, but promotes blockade of neuromuscular transmission. Chemical modifications of His, Lys, Tyr, and Trp residues of PrTX-I and PrTX-III were performed, together with cleavage of the N-terminal octapeptide by CNBr and inhibition by heparin and EDTA. The lethality, bactericidal activity, myotoxicity, neuromuscular effect, edema inducing effect, catalytic and anticoagulant activities, and the liposome-disruptive activity of the modified toxins were evaluated. A complex pattern of functional differences between the modified and native toxins was observed. However, in general, chemical modifications that significantly affected the diverse pharmacological effects of the toxins did not influence catalytic or membrane disrupting activities. Analysis of structural changes by circular dichroism spectroscopy demonstrated significant changes in the secondary structure only in the case of N-terminal octapeptide cleavage. These data indicate that PrTX-I and PrTX-III possess regions other than the catalytic site, which determine their toxic and pharmacological activities.
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Affiliation(s)
- A M Soares
- Departamento de Bioquímica e Immunologia, Faculdade de Medicina, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
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de Castro RC, Landucci EC, Toyama MH, Giglio JR, Marangoni S, De Nucci G, Antunes E. Leucocyte recruitment induced by type II phospholipases A(2) into the rat pleural cavity. Toxicon 2000; 38:1773-85. [PMID: 10858516 DOI: 10.1016/s0041-0101(00)00107-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bothropstoxin-I (BthTX-I) and bothropstoxin-II (BthTX-II) are Lys-49 and Asp-49 phospholipases A(2) (PLA(2)s), respectively, isolated from Bothrops jararacussu venom. Piratoxin-I (PrTX-I) is a Lys-49 PLA(2) isolated from Bothrops pirajai venom. In this study, the ability of BthTX-I, BthTX-II and PrTX-I to recruit leucocytes into the rat pleural cavity and potential mechanisms underlying this effect were investigated. Intrapleural injection of either BthTX-I or PrTX-I (10-100 microg/cavity each) caused a significant leucocyte infiltration at 12 h after injection. The maximal cell migration was observed with the dose of 30 microg/cavity (14.9+/-15.5 and 17.6+/-1. 6x10(6) cells/cavity, respectively). Leucocyte counts consisted mainly of mononuclear cells, but significant amounts of neutrophils and eosinophils were also observed. Intrapleural injection of BthTX-II (10-100 microg/cavity) caused a marked leucocyte infiltration at 6 and 12 h after injection. The maximal response was observed with the dose of 100 microg/cavity (57.3+/-3.4x10(6) cells/cavity, 6 h). The leucocyte counts were mainly composed of neutrophils and mononuclear cells. The treatment of either BthTX-I (30 microg/cavity, 12 h) or BthTX-II (30 microg/cavity, 6 h) with the PLA(2) inhibitor p-bromophenacyl bromide (p-BPB) had no effect on the total and differential leucocyte counts induced by these proteins. The same treatment partially reduced the PrTX-I-induced pleural leucocyte infiltration. In rats depleted of the histamine and 5-hydroxytryptamine (5-HT) stores by chronic treatment with compound 48/80, the total leucocyte counts in response to BthTX-I, BthTX-II and PrTX-I was not significantly affected compared to control animals. In addition, BthTX-I, BthTX-II and PrTX-I (100 microg/ml each) significantly degranulated pleural mast cells in vitro leading to the release of [(14)C]5-hydroxytryptamine ([(14)C]5-HT). p-BPB and heparin (50 IU/ml) significantly reduced the [(14)C]5-HT release induced by these PLA(2)s. Our results demonstrate that BthTX-I, BthTX-II and PrTX-I recruit leucocyte into the pleural cavity of the rat by mechanisms unrelated to enzymatic activity and pleural mast cell degranulation.
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Affiliation(s)
- R C de Castro
- Department of Pharmacology, Faculty of Medical Sciences, UNICAMP, PO Box 6111, 13081-970, (SP), Campinas, Brazil
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43
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Zhao K, Zhou Y, Lin Z. Structure of basic phospholipase A2 from Agkistrodon halys Pallas: implications for its association, hemolytic and anticoagulant activities. Toxicon 2000; 38:901-16. [PMID: 10728829 DOI: 10.1016/s0041-0101(99)00193-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The basic phospholipase A2 (PLA2) from the venom of Agkistrodon halys Pallas is a potent hemolytic toxin and anticoagulant. Crystal structure of the enzyme complexed with detergent n-octyl beta-D-glucopyranoside (beta-OG) in monoclinic crystal form has been determined to 2.6 A resolution. Beta-OG molecules were found in the hydrophobic channels of the enzyme. SDS-PAGE and dynamic light scattering measurements showed that the enzyme had a strong tendency to dimerise in aqueous solution. In the crystal structure the enzyme molecules associate into a tetramer with pseudo 222 symmetry, and the interfacial recognition site linked dimers constituting the tetramer have intensive interface interactions, and may be stable in solution. The structure reveals a unique positively charged face at the C-terminal region and a characteristic non-cationic 'anticoagulant' region (53-77). The face is supposed to be the hemolytic site, and based on sequence and structure comparison residues Trp70 and Glu53 instead of the basic residues in 'anticoagulant' region might play an important role in the anticoagulant activity.
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Affiliation(s)
- K Zhao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, Beijing, China
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Landucci EC, de Castro RC, Toyama M, Giglio JR, Marangoni S, De Nucci G, Antunes E. Inflammatory oedema induced by the lys-49 phospholipase A(2) homologue piratoxin-i in the rat and rabbit. Effect of polyanions and p-bromophenacyl bromide. Biochem Pharmacol 2000; 59:1289-94. [PMID: 10736429 DOI: 10.1016/s0006-2952(00)00248-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Piratoxin-I (PrTX-I) is a Lys-49 phospholipase (PLA(2)) homologue, isolated from Bothrops pirajai snake venom, that has no phospholipase activity. In this study, we investigated the in vivo oedematogenic activity of PrTX-I in both the rat and the rabbit as well as the ability of PrTX-I to activate rat mast cells in vitro. In the rat paw and skin, PrTX-I (3-100 microg/paw) induced a dose-dependent oedema that was associated with extensive mast cell degranulation. The involvement of mast cells in PrTX-I-mediated oedema formation in the rat was further confirmed by the findings that this protein significantly activated rat peritoneal mast cells in vitro, causing the release of [(14)C]5-hydroxytryptamine ([(14)C]5-HT; 51 +/- 1%). In the rabbit, PrTX-I (10-100 microg/site) also induced dose-dependent skin oedema formation that was not affected by either mepyramine (a histamine H(1) receptor antagonist) or cyproheptadine (1.0 microg/site), indicating that mast cells do not play a role in this animal species. The bradykinin B(2) receptor antagonist Hoe 140 (0.5 microg/site) and the platelet-activating factor (PAF) receptor antagonist WEB 2086 (200 microg/site) also failed to affect the PrTX-I-induced rabbit skin oedema, ruling out the involvement of kinins and PAF. The PLA(2) inhibitor p-bromophenacyl bromide greatly reduced the PrTX-I-induced oedema in both the rat and the rabbit, and also inhibited the rat in vitro mast cell activation induced by this PLA(2) homologue. The polyanions heparin and dermatan sulphate efficiently prevented oedema formation in both species, and heparin inhibited PrTX-I-induced rat mast cell degranulation. Our results are consistent with the suggestion that the cationic charge of PrTX-I plays a major role in the inflammatory responses induced by this PLA(2) homologue.
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Affiliation(s)
- E C Landucci
- Department of Pharmacology, UNICAMP, 13081-970, Campinas, SP, Brazil.
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45
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Soares AM, Andrião-Escarso SH, Angulo Y, Lomonte B, Gutiérrez JM, Marangoni S, Toyama MH, Arni RK, Giglio JR. Structural and functional characterization of myotoxin I, a Lys49 phospholipase A(2) homologue from Bothrops moojeni (Caissaca) snake venom. Arch Biochem Biophys 2000; 373:7-15. [PMID: 10620318 DOI: 10.1006/abbi.1999.1492] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myotoxin-I (MjTX-I) was purified to homogeneity from the venom of Bothrops moojeni by ion-exchange chromatography on CM-Sepharose. Its molecular weight, estimated by SDS-PAGE, was 13,400 (reduced) or 26, 000 (unreduced). The extinction coefficient (E(1.0 mg/ml)(1.0 cm)) of MjTX-I was 1.145 at lambda = 278 nm, pH 7.0, and its isoelectric point was 8.2 at ionic strength mu = 0.1. When lyophilized and stored at 4 degrees C, dimeric, trimeric, and pentameric forms of the protein were identified by SDS-PAGE. This "heterogeneous" sample could be separated into three fractions by gel filtration on Sephadex G-50. The fractions were analyzed by isoelectric focusing, immunoelectrophoresis, and amino acid composition, which indicated that heterogeneity was the result of different levels of self-association. Protein sequencing indicated that MjTX-I is a Lys49 myotoxin and consists of 121 amino acids (M(r) = 13,669), containing a high proportion of basic and hydrophobic residues. It shares a high degree of sequence identity with other Lys49 PLA(2)-like myotoxins, but shows a significantly lower identity with catalytically active Asp49 PLA(2)s. The three-dimensional structure of MjTX-I was modeled based on the crystal structures of three highly homologous Lys49 PLA(2)-like myotoxins. This model showed that the amino acid substitutions are conservative, and mainly limited to three structural regions: the N-terminal helix, the beta-wing region, and the C-terminal extended random coil. MjTX-I displays local myotoxic and edema-inducing activities in mice, and is lethal by intraperitoneal injection, with an LD(50) value of 8.5 +/- 0.8 mg/kg. In addition, it is cytotoxic to myoblasts/myotubes in culture, and disrupts negatively charged liposomes. In comparison with the freshly prepared dimeric sample, the more aggregated forms showed significantly reduced myotoxic activity. However, the edema-inducing activity of MjTX-I was independent of molecular association. Phospholipase A(2) activity on egg yolk, as well as anticoagulant activity, were undetectable both in the native and in the more associated forms. His, Tyr, and Trp residues of the toxin were chemically modified by specific reagents. Although the myotoxic and lethal activities of the modified toxins were reduced by these treatments, neither its edema-inducing or liposome-disrupting activities were significantly altered. Rabbit antibodies to native MjTX-I cross-reacted with the chemically modified forms, and both the native and modified MjTX-I preparations were recognized by antibodies against the C-terminal region 115-129 of myotoxin II from B. asper, a highly Lys49 PLA(2)-homologue with high sequencial similarity.
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Affiliation(s)
- A M Soares
- Faculdade de Medicina, Universidade de São Paulo, Ribeirão Preto-SP, 14049-900, Brazil
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46
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Melo PA, Ownby CL. Ability of wedelolactone, heparin, and para-bromophenacyl bromide to antagonize the myotoxic effects of two crotaline venoms and their PLA2 myotoxins. Toxicon 1999; 37:199-215. [PMID: 9920492 DOI: 10.1016/s0041-0101(98)00183-4] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined the ability of wedelolactone, heparin and para-bromophenacyl bromide to antagonize the myotoxic activity in mice of venoms from Crotalus viridis viridis and Agkistrodon contortrix laticinctus and two phospholipase A2 myotoxins, CVV myotoxin and ACL myotoxin, isolated from them. Myotoxicity was measured by the increase in plasma creatine kinase (CK) activity at two hours and histological changes in extensor digitorum longus muscle (EDL) at three hours after injection of the test solution. Both heparin and wedelolactone independently reduced the myotoxic effect of both crude venoms and both myotoxins, but wedelolactone was more effective. Wedelolactone plus heparin reduced the myotoxic effect of CVV myotoxin more than either antagonist alone. The PLA2 inhibitor, para-bromophenacyl bromide (pBPB), reduced the myotoxic effect of both myotoxins more than either wedelolactone or heparin. On the other hand, the myotoxic effect of polylysine was not reduced by either wedelolactone or para-bromophenacyl bromide, but it was reduced by heparin. These results indicate that wedelolactone, para-bromophenacyl bromide and heparin are antagonists of these two phospholipase A2 myotoxins, and that antagonism by the first two compounds may be due to a more specific interaction with these proteins than that by the latter.
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Affiliation(s)
- P A Melo
- Departamento de Farmacologia Basica e Clinica, Instituto de Ciencias Biomedicas, Universidade Federal do Rio de Janeiro, Brazil
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