Isolation and Partial Characterization of a Presynaptic Neurotoxic PLA2, Neuwieditoxin-II (NeuTX-II), from Bothrops neuwiedi pauloensis (Jararaca-Pintada) Snake Venom. 

1Borja-Oliveira, C.R.; ¹Hernandez-Oliveira, S.S., ²Toyama, M.H.; 2Marangoni, S. and 1Rodrigues-Simioni, L.

1 Depto. Farmacologia, FCM, 2 Depto. Bioquímica, IB, UNICAMP, Campinas, SP, Brazil.

A presynaptic phospholipase A2 (PLA2), neuwieditoxin-II (NeuTX-II), was isolated from Bothrops neuwiedi pauloensis snake venom. The PLA2 was purified by molecular exclusion HPLC, followed by reverse phase HPLC. Tricine SDS-PAGE in the absence or presence of dithiothreitol showed that NeuTX-II had a molecular mass of ~28 and ~14 kDa, respectively. NeuTX-II (10 mg/ml) produced complete neuromuscular blockade in indirectly stimulated isolated chick biventer cervicis preparations in 85.0 ± 5.0 min (mean ± S.E.M; n=3), without inhibiting acetylcholine-induced contracture, but reduced the response to KCl by 67.0 ± 8.0% (n=3; p < 0.05). The N-terminal sequence of NeuTX-II was SLFEFAKMILEETKRLPFPYYGAYGCYCGWGGQGQPKDAT and showed 92% homology to the Asp49 PLA2 myotoxin Basp-III and 62% homology with the presynaptic PLA2 neurotoxins crotoxin (basic component), trimucrotoxin and ammodytoxin. The observation that NeuTX-II had Phe-5 and Tyr-28, amino acid residues conserved in all Asp49 PLA2 variants purified so far, and that its amino acid sequence was similar to Asp49 PLA2, strongly suggested that NeuTX-II was a Asp49 PLA2.

NeuTX-II may be one of the responsible for the presynaptic and myotoxic effects of B. n. pauloensis venom in vitro.

Support : CAPES and FAPESP.

Correspondence to: saher@unicamp.br