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Type: Artigo de periódico
Title: Sequence and structure-activity relationship of a scorpion venom toxin with nitrergic activity in rabbit corpus cavernosum
Author: Teixeira, CE
Ifa, DR
Corso, G
Santagada, V
Caliendo, G
Antunes, E
De Nucci, G
Abstract: An alpha-toxin responsible for nitric oxide (NO) release in rabbit corpus cavernosum (RbCC) was isolated from Tityus serrulatus venom (TSV). The isolated peptide (molecular mass of 7427.66+/-0.15 Da) was identified as Ts3 after determination of Cys residues, N-terminal amino acid analysis, and proteolytic peptide mapping. Ts3 (30 nM) markedly relaxed the RbCC; this response was blocked by the NO synthesis inhibitor N-omega-nitro-L-arginine methyl ester (100 muM) and the Na+ channel blocker tetrodotoxin (100 nM). Synthetic peptides based on either Ts3 (P1-16, P17-32, P33-48, P49-64, P9-24, P25-40, P41-56, YGLPDKVPTKT) or Bukatoxin (isolated from Buthus martensi Karsch scorpion venom) sequence (Buka11, Buka11-B, PDKVP, PDSEP) were assayed. These peptides slightly relaxed the RbCC, and such an effect was independent of Na+ channel activation or NO release. Our results indicate that Ts3 exerts nitrergic actions and contributes to the relaxing activity of TSV in RbCC, thus providing a valuable tool to investigate the mechanisms underlying nerve activation in erectile tissues, because NO released from nitrergic fibers plays a key role in the erectile process. Our findings revealed the key importance of the Ts3 structure three-dimensional conformation maintenance for biological activity, because linear peptide sequences neither presented substantial relaxations nor was this effect related to nitrergic activity.
Subject: nitric oxide
Tityus serrulatus
sodium channels
erectile tissue
Country: EUA
Editor: Federation Amer Soc Exp Biol
Rights: fechado
Identifier DOI: 10.1096/fj.02-0635fje
Date Issue: 2003
Appears in Collections:Unicamp - Artigos e Outros Documentos

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