| serum il-6, tnfα levels in snakebite cases occurring in southern turkey. | the snake species vipera ammodytes meridionalis and vipera lebetina obtuse are often seen in southern turkey and have venom that causes serious systemic and tissue damage. the aim of our study is to assess the relationship between tumour necrosis factor α (tnfα) and interleukin 6 (il-6) serum levels, and clinical and laboratory findings in the snakebite patients. | 2011 | 20595711 |
| Venom peptide analysis of Vipera ammodytes meridionalis (Viperinae) and Bothrops jararacussu (Crotalinae) demonstrates subfamily-specificity of the peptidome in the family Viperidae. | Snake venom peptidomes are valuable sources of pharmacologically active compounds. We analyzed the peptidic fractions (peptides with molecular masses < 10,000 Da) of venoms of Vipera ammodytes meridionalis (Viperinae), the most toxic snake in Europe, and Bothrops jararacussu (Crotalinae), an extremely poisonous snake of South America. Liquid chromatography/mass spectrometry (LC/MS), direct infusion electrospray mass spectrometry (ESI-MS) and matrix-assisted desorption/ionization time-of-flight m ... | 2011 | 21959992 |
| acute toxicity of vipoxin and its components: is the acidic component an "inhibitor" of pla2 toxicity? | vipoxin is a heterodimeric neurotoxin isolated from the venom of the bulgarian long-nosed viper vipera ammodytes meridionalis. vipoxin represents a noncovalent association of two subunits - a basic and toxic phospholipase a2 enzyme, and an acidic non-enzymatic component (vipoxin's acidic component). it was postulated that the phospholipase a2 subunit was more toxic than the whole vipoxin complex and the function of the acidic component was to reduce the enzymatic and toxic activities of the basi ... | 2012 | 23554559 |
| biochemical and biological properties of phospholipases a(2) from bothrops atrox snake venom. | phospholipases a(2) (pla(2)s), of molecular mass 13-15kda, are commonly isolated from snake venom. two myotoxins with pla(2) activity, bapla(2)i and bapla(2)iii, with estimated molecular masses of 15kda were isolated from the venom of bothrops atrox using sephacryl s-100-hr and reverse-phase chromatography. bapla(2)i was basic, with a pi of 9.1, while bapla(2)iii was neutral with a pi of 6.9. on a molecular basis, bapla(2)iii exhibited higher catalytic activity on synthetic substrates than bapla ... | 2002 | 12234622 |
| snake venomics of the siamese russell's viper (daboia russelli siamensis) -- relation to pharmacological activities. | the venom proteome of daboia russelli siamensis, a snake of medical importance in several asian countries, was analysed by 2-d electrophoresis, subsequent ms/ms and enzymatic assays. the proteome comprises toxins from six protein families: serine proteinases, metalloproteinases, phospholipases a(2), l-amino acid oxidases, vascular endothelial growth factors and c-type lectin-like proteins. the venom toxin composition correlates with the clinical manifestation of the russell's viper bite and expl ... | 2009 | 19457351 |
| enzymatic activity and inhibition of the neurotoxic complex vipoxin from the venom of vipera ammodytes meridionalis. | vipoxin from the venom of vipera ammodytes meridionalis is an unique neurotoxic complex between a toxic phospholipase a2 and a highly homologous non-toxic protein inhibitor. it is an example of evolution of a catalytic and toxic function into inhibitory and non-toxic one. the activity of the v. ammodytes meridionalis toxin is 1.7 times higher than that of the closely related (92% sequence identity) neurotoxic complex rv4/rv7 from the venom of vipera russelli formosensis the enhanced enzymatic ac ... | 2016 | 12562098 |
| effects of vipoxin and its components on hepg2 cells. | snake venom phospholipases a2 (svpla2) are among the main toxic venom components with a great impact on different tissues and organs based on their catalytic specificity and a variety of pharmacological effects, whose mechanism is still under debate. the main toxic component, isolated from the venom of vipera ammodytes meridionalis, is the heterodimeric postsynaptic ionic complex vipoxin, composed of a basic and toxic pla2 enzyme subunit (giia secreted pla2) and an acidic, enzymatically inactive ... | 2015 | 25534906 |
| hemolytic activity and platelet aggregation inhibitory effect of vipoxin's basic spla2 subunit. | in the present study we evaluated the effect of secreted phospholipase a2 (spla2) (the toxic subunit of the heterodimeric neurotoxin vipoxin, isolated from the bulgarian long-nosed viper vipera ammodytes meridionalis) on hemolysis, erythrocyte morphology and platelet aggregation. hemolytic activity of spla2 was examined in the presence of saturated (palmitic) and unsaturated (oleic) fatty acids and it was found that oleic acid increased the hemolytic activity of spla2 in a concentration-dependen ... | 2013 | 24678250 |
| recognition of vipera ammodytes meridionalis neurotoxin vipoxin and its components using phage-displayed scfv and polyclonal antivenom sera. | vipoxin is a potent postsynaptic heterodimeric neurotoxin isolated from the venom of the bulgarian snake vipera ammodytes meridionalis, whose snakebites cause different and strongly manifested pathophysiological effects (neurotoxic, hemolytic, anticoagulant, convulsant, hypotensive, hyperglycemic etc.). the neutralization of snake toxins calls for extensive research through the application of different approaches: antibodies, non-immunologic inhibitors, natural products derived from plants and a ... | 2012 | 22750218 |
| vipoxin and its components: structure-function relationship. | the neurotoxin vipoxin has been of growing research interest since the time of its isolation from the venom of the bulgarian viper vipera ammodytes meridionalis. vipoxin is a heterodimeric postsynaptic ionic complex composed of two protein subunits-a basic and strongly toxic his48 secretory phospholipase a(2) (spla(2)) enzyme and an acidic, enzymatically inactive and nontoxic component, originally named inhibitor. when separated, spla(2) enzyme loses its toxicity in 3-4 days and catalytic activi ... | 2012 | 22607754 |
| crystal structure of a dimeric ser49- pla₂-like myotoxic component of the vipera ammodytes meridionalis venomics reveals determinants of myotoxicity and membrane damaging activity. | myotoxicity and membrane damage play a central role in the life-threatening effects of the viper envenomation. myotoxins are an important part of the viper venomics. a ser49 pla₂-like myotoxin from the venom of vipera ammodytes meridionalis, the most venomous snake in europe, was crystallized and its three-dimensional structure determined. the toxin is devoid of phospholipolytic activity. the structure demonstrates a formation of dimers. in the dimers functionally important peptide segments, loc ... | 2012 | 22362132 |
| hemolytic and anticoagulant study of the neurotoxin vipoxin and its components--basic phospholipase a2 and an acidic inhibitor. | in the present study, we demonstrate for the first time that the potent neurotoxin vipoxin from the venom of vipera ammodytes meridionalis exhibits hemolytic and anticoagulant properties. by investigating the effects of phospholipids and calcium ions on hemolysis, we established that the phospholipase a2 (pla2) enzyme activity is responsible for the hemolytic properties. this was confirmed by chemical modification of the pla2 active-site histidine residue with p-bromophenacylbromide. applying di ... | 2009 | 19364321 |
| comparative analysis of the venom proteomes of vipera ammodytes ammodytes and vipera ammodytes meridionalis. | the venom proteomics of vipera ammodytes ammodytes and vipera ammodytes meridionalis, snakes of public health significance and the most poisonous reptiles in europe, were analyzed by fplc, 2-d electrophoresis, sequence analysis, and ms/ms. fplc analysis showed the presence of l-amino acid oxidase, monomeric and heterodimeric phospholipases a2, c-type lectin protein, and proteinases in the venom of v. a. ammodytes. representatives of the same protein families were found in the venom of the other ... | 2008 | 18257516 |
| asp49 phospholipase a(2)-elaidoylamide complex: a new mode of inhibition. | the inhibition of phospholipase a(2)s (pla(2)s) is of pharmacological and therapeutic interest because these enzymes are involved in several inflammatory diseases. elaidoylamide is a powerful inhibitor of a neurotoxic pla(2) from the vipera ammodytes meridionalis venom. the x-ray structure of the enzyme-inhibitor complex reveals a new mode of asp49 pla(2) inhibition by a fatty acid hydrocarbon chain. the structure contains two identical homodimers in the asymmetric unit. in each dimer one subuni ... | 2004 | 15194511 |
| the x-ray structure of a snake venom gln48 phospholipase a2 at 1.9a resolution reveals anion-binding sites. | phospholipase a2 is an "interfacial" enzyme and its binding to negatively charged surfaces is an important step during catalysis. the gln48 phospholipase a2 from the venom of vipera ammodytes meridionalis plays the role of chaperone and directs a toxic his48 pla2 onto its acceptor. in the venom the two phospholipases a2 exist as a postsynaptic neurotoxic complex, vipoxin. the x-ray structure of gln48 pla2, complexed to sulphate ions, which mimic the negatively charged groups of anionic membranes ... | 2004 | 15003507 |
| interactions of the neurotoxin vipoxin in solution studied by dynamic light scattering. | the neurotoxin vipoxin is the lethal component of the venom of vipera ammodytes meridionalis. it is a heterodimer of a basic toxic his-48 phospholipase a2 (pla2) and an acidic nontoxic gln-48 pla2. the shape of the neurotoxin and its separated components in solution as well as their interactions with calcium, the brain phospholipid phosphatidylcholine, and two inhibitors, elaidoylamide and vitamin e, were investigated by dynamic light scattering. calcium binding is connected with a conformationa ... | 2004 | 14695289 |
| crystallization and preliminary x-ray diffraction studies of a toxic phospholipase a2 from the venom of vipera ammodytes meridionalis complexed to a synthetic inhibitor. | a toxic phospholipase a(2) (pla(2)) is isolated from the neurotoxic complex vipoxin, the major lethal component of the venom of vipera ammodytes meridionalis. the enzyme is complexed to the synthetic inhibitor elaidoylamide and crystallized. the crystals belong to the space group p2(1)2(1)2(1), with unit cell dimensions a=46.57 a, b=82.68 a, c=119.47 a and beta=90 degrees. initial diffraction data to 3.3 a resolution are collected. | 2003 | 12922163 |
| structure-function relationships in the neurotoxin vipoxin from the venom of vipera ammodytes meridionalis. | the neurotoxic complex vipoxin is the lethal component of the venom of vipera ammodytes meridionalis, the most toxic snake in europe. it is a complex between a toxic phospholipase a2 (pla2) and a non-toxic and catalytically inactive protein, stabilizing the enzyme and reducing the activity and toxicity. structure-function relationships in this complex were studied by spectroscopic methods. a good correlation between the ionization behaviour and accessible surface area (asa) of the tyrosyl residu ... | 2003 | 12524132 |
| toxicity evolution of vipera aspis aspis venom: identification and molecular modeling of a novel phospholipase a(2) heterodimer neurotoxin. | we report the simultaneous presence of two phospholipase a(2) (pla(2)) neurotoxins in the venom of vipera aspis aspis, the first such observation. one is monomeric and identical to ammodytoxin b of vipera ammodytes ammodytes. its presence may result from gene flux after interbreeding between v. aspis aspis and v. ammodytes ammodytes. the second, a novel heterodimer named vaspin, is very similar to vipoxin of vipera ammodytes meridionalis and to pla(2)-i of vipera aspis zinnikeri. it may result f ... | 2002 | 12220671 |
| structure of the neurotoxic complex vipoxin at 1.4 a resolution. | vipoxin is a neurotoxic postsynaptic heterodimeric complex from the venom of vipera ammodytes meridionalis, the most toxic snake in europe. it consists of a basic and highly toxic phospholipase a(2) and an acidic non-toxic protein inhibitor. the two polypeptide chains have the same chain length and share 62% amino-acid identity. vipoxin is a unique example of evolution of the catalytic and toxic phospholipase a(2) functions into inhibitory and non-toxic functions. the crystal structure of the co ... | 2001 | 11679719 |
| modulation of phospholipase a2 activity generated by molecular evolution. | snake venom oligomeric neurotoxins offer several unique examples of modulation of phospholipase a2 (pla2) activity generated by molecular evolution. this phenomenon was found in evolutionary younger snakes and is probably common for representatives of the genus vipera. at present, the best-studied example is the heterodimeric neurotoxin vipoxin from the venom of the southeast european snake vipera ammodytes meridionalis. it is a complex between a basic strongly toxic pla2 and an acidic and catal ... | 1999 | 11212293 |
| spectroscopic investigation of calcium binding sites in the neurotoxin vipoxin and its components-relation with the x-ray structure. | vipoxin is a neurotoxin from the venom of vipera ammodytes meridionalis, the most toxic snake in europe. it is a unique complex of a toxic phospholipase a2 (pla2) and a non-toxic pla2-like protein inhibitor (inh) which probably evolved from the enzyme and reduces its activity and toxicity. the enzymatic activity of vipoxin is ca2+-dependent and the interaction of this metal ion with the neurotoxic complex and its separated components was investigated using the fluorescent probe ans. vipoxin bind ... | 2000 | 11145348 |
| spectroscopic properties and stability of the neurotoxic complex. vipoxin and its components. | the neurotoxin vipoxin from the venom of vipera ammodytes meridionalis is a complex between a toxic basic phospholipase a2 (pla2) and a non-toxic acidic protein inhibitor (inh). tryptophan fluorescence parameters are determined for the complex and for its components. iodide, caesium and acrylamide are not efficient quenchers of the vipoxin indole emission. increased accessibilities of tryptophans to ionic and neutral quenchers are found after the dissociation of the complex. trp 20 and trp 31 be ... | 1998 | 9698946 |
| crystal structure of vipoxin at 2.0 a: an example of regulation of a toxic function generated by molecular evolution. | vipoxin is the main toxic component in the venom of the bulgarian snake vipera ammodytes meridionalis, the most toxic snake in europe. vipoxin is a complex between a toxic phospholipase a2 (pla2) and a non-toxic protein inhibitor. the structure is of genetic interest due to the high degree of sequence homology (62%) between the two functionally different components. the structure shows that the formation of the complex in vipoxin is significantly different to that seen in many known structures o ... | 1997 | 9276469 |