Structural and functional characterization of N-terminally blocked peptides isolated from the venom of the social wasp Polybia paulista

Autor(es)

Ribeiro, Susan Pereira ; Mendes, Maria Anita ^[2] ; Santos, Lucilene Delazari dos ; Souza, Bibiana Monson de ; Marques, Maurício Ribeiro ; Azevedo Junior, Walter Filgueira de ; Palma, Mario Sergio

• Tipo de documento: Artigo Científico
• Fonte: Peptides; v. 25, n. 12, p. 2069-2078, Dec. 2004.
• Área do conhecimento: Ciências Biológicas - Bioquímica
• Assunto(s): Peptídeos Espectrometria de massas Venenos de origem animal Vespas Polybia paulista

Resumo

Two novel peptides were isolated from the crude venom of the social wasp Polybia paulista, by using RP-HPLC under a gradient of MeCN from 5 to 60% (v/v) and named Polybine-I and -II. Further purification of these peptides under normal phase chromatography, rendered pure enough preparations to be sequenced by Edman degradation chemistry. However, both peptides did not interact with phenylisothiocyanate reagent, suggesting the existence of a chemically blocked N-terminus. Therefore, the sequences of both peptides were assigned by ESI-MS/MS under CID conditions, as follows: Polybine-I Ac-SADLVKKIWDNPAL-NH2 (Mr 1610 Da) and Polybine-II Ac-SVDMVMKGLKIWPL-NH2 (Mr 1657 Da). During the tandem mass spectrometry experiments, a loss of 43 a.m.u. was observed from the N-terminal residue of each peptide, suggesting the acetylation of the N-terminus. Subsequently, the peptides with and without acetylation were synthesized on solid phase and submitted to functional characterizations; the biological activities investigated were: hemolysis, chemotaxis of polymorphonucleated leukocytes (PMNL), mast cell degranulation and antibiosis. The results revealed that the acetylated peptides exhibited more pronounced chemotaxis of PMNL cells and mast cell degranulation than the respective non-acetylated congeners; no hemolytic and antibiotic activities were observed, irrespective to the blockage or not of the α-amino groups of the N-terminal residues of each peptide. Therefore, the N-terminal acetylation may be related to the increase of the inflammatory activity of both peptides. (AU)

• Processo FAPESP: 01/05060-4 - Caracterizacao estrutural de peptideos biologicamente ativos das peconhas de vespas sociais e solitarias, por espectrometria de massas.
• Beneficiário: Maria Anita Mendes
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 01/07532-0 - Structural genomics of cyclin dependent kinases and plant defensive proteinases and their natural inhibitors
• Beneficiário: Walter Filgueira de Azevedo Junior
• Modalidade de apoio: Auxílio à Pesquisa - Regular