ABSTRACT
Snake venom metalloproteinases (SVMPs) participate in a number of important biological, physiological and pathophysiological processes and are primarily responsible for the local tissue damage characteristic of viperid snake envenomations. The use of medicinal plant extracts as antidotes against animal venoms is an old practice, especially against snake envenomations. Such plants are sources of many pharmacologically active compounds and have been shown to antagonize the effects of some venoms and toxins. The present study explores the activity of triacontyl p-coumarate (PCT), an active compound isolated from root bark of Bombacopsis glabra vegetal extract (Bg), against harmful effects of Bothropoides pauloensis snake venom and isolated toxins (SVMPs or phospholipase A(2)). Before inhibition assays, Bg or PCT was incubated with venom or toxins at ratios of 1:1 and 1:5 (w/w; venom or isolated toxins/PCT) for 30 min at 37°C. Treatment conditions were also assayed to simulate snakebite with PCT inoculated at either the same venom or toxin site. PCT neutralized fibrinogenolytic activity and plasmatic fibrinogen depletion induced by B. pauloensis venom or isolated toxin. PCT also efficiently inhibited the hemorrhagic (3MDH - minimum hemorrhagic dose injected i.d into mice) and myotoxic activities induced by Jararhagin, a metalloproteinase from B. jararaca at 1:5 ratio (toxin: inhibitor, w/w) when it was previously incubated with PCT and injected into mice or when PCT was administered after toxin injection. Docking simulations using data on a metalloproteinase (Neuwiedase) structure suggest that the binding between the protein and the inhibitor occurs mainly in the active site region causing blockade of the enzymatic reaction by displacement of catalytic water. Steric hindrance may also play a role in the mechanism since the PCT hydrophobic tail was found to interact with the loop associated with substrate anchorage. Thus, PCT may provide a alternative to complement ophidian envenomation treatments.
Subject(s)
Coumaric Acids/chemistry , Coumaric Acids/pharmacology , Metalloproteases/antagonists & inhibitors , Metalloproteases/metabolism , Plant Extracts/chemistry , Plant Extracts/pharmacology , Snake Venoms/enzymology , AnimalsABSTRACT
Crotoxin B is a basic phospholipase A(2) found in the venom of several Crotalus durissus ssp. rattlesnakes and is one of the subunits that constitute crotoxin, the main component of the venom of these snakes. This heterodimeric toxin is related to important envenomation effects such as neurological disorders, myotoxicity and renal failure. Although crotoxin was first crystallized in 1938, the first structural data only became available in 2007 (for crotoxin B from C. durissus terrificus) and showed an ambiguous result for the biological assembly, which could be either dimeric or tetrameric. In this work, the crystallization, X-ray diffraction data collection at 2.2 A resolution and molecular-replacement solution of a dimeric complex formed by two crotoxin B isoforms from C. durissus collilineatus venom is presented.
Subject(s)
Crotoxin/chemistry , Animals , Crotalid Venoms/chemistry , Crotoxin/isolation & purification , Crystallization , Crystallography, X-Ray , Dimerization , Phospholipases A2/chemistry , Protein Structure, QuaternaryABSTRACT
Crotoxin B is a basic phospholipase A2 found in the venom of Crotalus durissus terrificus and is one of the subunits that constitute crotoxin. This heterodimeric toxin, which is the main component of C. d. terrificus venom, is completed by an acidic, nontoxic and non-enzymatic component (crotoxin A) and is involved in important envenomation effects, such as neurological disorders, myotoxicity and renal failure. Although crotoxin was first crystallized in 1938, no crystal structure is currently available for crotoxin, crotoxin A or crotoxin B. In this work, the crystallization, X-ray diffraction data collection to 2.28 A resolution and molecular-replacement solution of a novel tetrameric complex formed by two dimers of crotoxin B isoforms (CB1 and CB2) is presented.
Subject(s)
Crotalus/metabolism , Crotoxin/chemistry , Crotoxin/metabolism , Phospholipases A2/chemistry , Phospholipases A2/metabolism , Snake Venoms/chemistry , Snake Venoms/metabolism , Animals , Crotalus/genetics , Crotoxin/genetics , Crystallization , Isoenzymes/chemistry , Isoenzymes/metabolism , Models, Molecular , Phospholipases A2/genetics , Protein Binding , Protein Structure, Quaternary , Snake Venoms/genetics , X-Ray DiffractionABSTRACT
For the first time, a complete X-ray diffraction data set has been collected from a myotoxic Asp49-phospholipase A2 (Asp49-PLA2) with low catalytic activity (BthTX-II from Bothrops jararacussu venom) and a molecular-replacement solution has been obtained with a dimer in the asymmetric unit. The quaternary structure of BthTX-II resembles the myotoxin Asp49-PLA2 PrTX-III (piratoxin III from B. pirajai venom) and all non-catalytic and myotoxic dimeric Lys49-PLA2s. In contrast, the oligomeric structure of BthTX-II is different from the highly catalytic and non-myotoxic BthA-I (acidic PLA2 from B. jararacussu). Thus, comparison between these structures should add insight into the catalytic and myotoxic activities of bothropic PLA2s.
Subject(s)
Asparagine , Bothrops , Crotalid Venoms/toxicity , Phospholipases A/toxicity , Animals , Catalysis , Crotalid Venoms/chemistry , Crotalid Venoms/metabolism , Crystallography, X-Ray , Kinetics , Phospholipases A/chemistry , Phospholipases A/isolation & purification , Phospholipases A/metabolism , Phospholipases A2 , Protein ConformationABSTRACT
For the first time, a non-catalytic and myotoxic Lys49-PLA2 (BthTX-I from Bothrops jararacussu venom) has been crystallized with BPB inhibitor. X-ray diffraction data were collected and electron-density calculations showed that the ligand is bound to the His48 residue. BthTX-I with His48 chemically modified by BPB shows strongly reduced myotoxic and cytotoxic activities. This suggests a biological correlation between the modification of His48, which is associated with catalytic activity of PLA2s, and other toxicological activities of Lys49-PLA2s.
Subject(s)
Acetophenones/chemistry , Crotalid Venoms/chemistry , Phospholipases A/chemistry , Animals , Bothrops , Catalysis , Crystallization/methods , Histidine/chemistry , Phospholipases A/metabolism , Phospholipases A/toxicity , Phospholipases A2 , Solvents , X-Ray DiffractionABSTRACT
A new myotoxic Lys49-phospholipase A2 isolated from Bothrops moojeni snake venom has been crystallized. The crystals diffracted to 2.18 A resolution using a synchrotron-radiation source and belong to space group C2. The unit-cell parameters are a = 56.8, b = 125.0, c = 64.7 A, beta = 105.5 degrees. Preliminary analysis indicates the presence of four molecules in the asymmetric unit. This may suggest a new quaternary structure for this Lys49-phospholipase A2 in contrast to the dimeric and monomeric structures solved so far for this class of proteins.
Subject(s)
Lysine/chemistry , Phospholipases A/chemistry , Snake Venoms/metabolism , Animals , Crystallization , Crystallography, X-Ray , Diffusion , Dimerization , Electrophoresis, Polyacrylamide Gel , Group II Phospholipases A2 , Isoelectric Focusing , Protein Conformation , Protein Structure, Quaternary , Protein Structure, Tertiary , Reptilian Proteins , Snakes , Synchrotrons , X-Ray DiffractionABSTRACT
Lys49-Phospholipase A2 (Lys49-PLA(2) - EC 3.1.1.4) homologues damage membranes by a Ca2+-independent mechanism which does not involve catalytic activity. Both MjTX-II from Bothrops moojeni and BthTX-I from Bothrops jararacussu are dimeric in solution and in the crystalline states, and a model for the Ca2+-independent membrane damaging mechanism has been suggested in which flexibility at the dimer interface region permits quaternary structural transitions between "open" and "closed" membrane bound dimer conformations which results in the perturbation of membrane phospholipids and disruption of the bilayer structure. With the aim of gaining insights into the structural determinants involved in protein/lipid association, we report here the crystallization and preliminary X-ray analysis of the (i) MjTX-II/SDS complex at a resolution of 2.78A, (ii) MjTX-II/STE complex at a resolution of 1.8 A and (iii) BthTX-I/DMPC complex at 2.72A. These complexes were crystallized by the hanging drop vapour-diffusion technique in (i) HEPES buffer (pH 7.5) 1.8M ammonium sulfate with 2% (w/v) polyethyleneglycol 400, in (ii) 0.6-0.8 M sodium citrate as the precipitant (pH 6.0-6.5) and in (iii) sodium citrate buffer (pH 5.8) and PEG 4000 and 20% isopropanol, respectively. Single crystals of these complexes have been obtained and X-ray diffraction data have been collected at room temperature using a R-AXIS IV imaging plate system and graphite monochromated Cu Kalpha X-ray radiation generated by a Rigaku RU300 rotating anode generator for (i) and (iii) and using using a Synchrotron Radiation Source (Laboratório Nacional de Luz Sincrotron, LNLS, Campinas, Brazil) for (ii).
Subject(s)
Crotalid Venoms/chemistry , Phospholipases A/chemistry , Animals , Crystallization , Dimyristoylphosphatidylcholine/chemistry , Phospholipases A2 , Sodium Dodecyl Sulfate/chemistry , Stearic Acids/chemistry , X-Ray Diffraction/statistics & numerical dataABSTRACT
This report documents a case of a melanic specimen of Crotalus durissus terrificus (Laurenti, 1768) found in Bofete, Säo Paulo State, Brazil. The authors describe this melanic snake, determine the electrophoretic pattern of its venom, and compare the venom of this specimen against that of normal Crotalus durissus terrificus. This report is very important because melanism is a rare chromatic anomaly.
Subject(s)
Animals , Crotalus , Melanosis , Crotalid Venoms/analysis , Brazil , ElectrophoresisABSTRACT
Polyacrylamide gel electrophoresis (PAGE) for basic proteins may be a useful toll for the characterization of whole snake venoms and for the taxonomic classification of snakes of the Elapidae and Viperidae families. However, due to the close proximity of PAGE was not able to provide an efficient differentiation. This article reports the electrophoretic analysis of several venoms from the genera Micrurus, Bothrops, Bothriopsis, Crotalus and Lachesis and shows a typical and distinctive electrophoretic profile for each species, with intraspecific and geographic variation. Even in cases in which extreme morphological similarities were present, such as between B. jararacussu and B. pirajai ("Bahia jararacussu"), differentiation could be evidenced by PAGE. This simple and sensitive procedure may be applied to similar cases involving basic toxins.