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Type: Artigo de periódico
Title: Structural, enzymatic and biological properties of new PLA(2) isoform from Crotalus durissus terrificus venom
Author: Toyama, MH
de Oliveira, DG
Beriam, LOS
Novello, JC
Rodrigues-Simioni, L
Marangoni, S
Abstract: We isolated a new PLA(2) from the Crotalus durissus terrificus venom that designated F15, which showed allosteric behavior with a V-max of 8.5 nmol/min/mg and a K-m of 38.5 mM. The incubated heparin salt of this isolated F15 act a positive allosteric effector by increasing the V-max to 10.2 nmol/min/mg, with decreasing the V-max value to 20.5 mM. The crotapotin, on the other hand acts as a negative allosteric effector by increasing the V-max values to 58.4 mM. F15 also showed high calcium dependence for its catalysis similar to that found for other PLA(2) enzymes isolated from these snake venoms. The replacement of calcium by other divalent ions such Mg2+, Mn2+, Cd2+, Sn2+ and Cu2+ resulted in lower enzymatic activity. The optimum pH and temperature for the enzyme was 8.5 and 18 T, respectively. F15 alone showed moderate neurotoxic activity in isolated mouse phrenic nerve diaphragm in comparison to other strong myotoxic PLA2 such as bothropstoxin-I (BThtx-1), but this activity was highly neurotoxic in a chick biventrer cervis preparation, whereas BthTx-I did not reveal this high neurotoxicity. This new protein showed a high bactericidal effect against both Gram-negative and Gram-positive bacterial strains. F15 contained 122 amino acid residues, with a primary structure of: HLLQFNKMIKFETRKNAVPFYAFYGCYCGWGGQRRPKDATDRCCFVHDCCYGKLTKCNTKWDIYRYSLKSGYITCGKGTWCKEQICECDRVAAECLRRSL- STYKNEYMFYPKSRCRRPSETC. Its molecular mass and isoeletric point were 14.5 kDa and 8.85, both estimated by two dimensional electrophoresis. The amino acid sequence of the F15 revealed high sequence homology with F16 and FIT F15 and the other PLA(2)s revealed highly conserved amino acid sequences principally for calcium binding loop and active site helix. F15 also showed a high homology with the lysine-rich region of myotoxic PLA(2). (C) 2003 Elsevier Science Ltd. All rights reserved.
Subject: bactericidal
Crotalus durissus terrificus
rattlesnake venom
Country: Inglaterra
Editor: Pergamon-elsevier Science Ltd
Citation: Toxicon. Pergamon-elsevier Science Ltd, v. 41, n. 8, n. 1033, n. 1038, 2003.
Rights: fechado
Identifier DOI: 10.1016/S0041-0101(03)00085-0
Date Issue: 2003
Appears in Collections:Unicamp - Artigos e Outros Documentos

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