Data/hora: 01/06/2024 17:50:57

Provedor de dados: | Journal of Venomous Animals and Toxins Including Tropical Diseases
País: | Brazil
Título: | Purification and n-terminal sequencing of two presynaptic neurotoxic PLA2, neuwieditoxin-I and neuwieditoxin-II, from Bothrops neuwiedi pauloensis (jararaca pintada) venom
Autores: | Borja-Oliveira,C. R.; Kassab,B. H.; Soares,A. M.; Toyama,M. H.; Giglio,J. R.; Marangoni,S.; Re,L.; Rodrigues-Simioni,L.
Data: | 2007-01-01
Ano: | 2007
Palavras-chave: | Chick biventer cervicis; Loose patch clamp; Nerve-muscle preparation; Neuromuscular junction; Neurotoxicity; PLA2 neurotoxin; Presynaptic action; Bothrops neuwiedi pauloensis; Neuwieditoxin-I; Neuwieditoxin-II.
Resumo: | Two presynaptic phospholipases A2 (PLA2), neuwieditoxin-I (NeuTX-I) and neuwieditoxin-II (NeuTX-II), were isolated from the venom of Bothrops neuwiedi pauloensis (BNP). The venom was fractionated using molecular exclusion HPLC (Protein-Pak 300SW column), followed by reverse phase HPLC (µBondapak C18 column). Tricine-SDS-PAGE in the presence or absence of dithiothreitol showed that NeuTX-I and NeuTX-II had a molecular mass of approximately 14 kDa and 28kDa, respectively. At 10µg/ml, both toxins produced complete neuromuscular blockade in indirectly stimulated chick biventer cervicis isolated preparation without inhibiting the response to acetylcholine, but NeuTX-II reduced the response to KCl by 67.0±8.0% (n=3; p&lt;0.05). NeuTX-I and NeuTX-II are probably responsible for the presynaptic neurotoxicity of BNP venom in vitro. In fact, using loose patch clamp technique for mouse phrenic nerve-diaphragm preparation, NeuTX-I produced a calcium-dependent blockade of acetylcholine release and caused appearance of giant miniature end-plate potentials (mepps), indicating a pure presynaptic action. The N-terminal sequence of NeuTX-I was DLVQFGQMILKVAGRSLPKSYGAYGCYCGWGGRGK (71% homology with bothropstoxin-II and 54% homology with caudoxin) and that of NeuTX-II was SLFEFAKMILEETKRLPFPYYGAYGCYCGWGGQGQPKDAT (92% homology with Basp-III and 62% homology with crotoxin PLA2). The fact that NeuTX-I has Q-4 (Gln-4) and both toxins have F-5 (Phe-5) and Y-28 (Tyr-28) strongly suggests that NeuTX-I and NeuTX-II are Asp49 PLA2.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-91992007000100008
Editor: | Centro de Estudos de Venenos e Animais Peçonhentos
Relação: | 10.1590/S1678-91992007000100008
Formato: | text/html
Fonte: | Journal of Venomous Animals and Toxins including Tropical Diseases  v.13 n.1 2007
Fonte: | info:eu-repo/semantics/openAccess