RESUMO
The use of mass spectrometry, in which high-energy CID and charge remote fragmentation both of protonated and sodium-attached molecular ions was applied, afforded the structural elucidation of a new acylpolyaminetoxin with Mw=801 Da from the venom of the Brazilian garden spider Nephilengys cruentata. In spite of having the same Mw of the NPTX-2, previously described in the venom of the Joro spider Nephila clavata, neither toxins are isomers. In order to differentiate them by using the most usual nomenclature, the new toxin was named NPTX-801C and the NPTX-2 was renamed to NPTX-801E. Both toxins have as common structure the 4-hydroxyindole-3-acetyl-asparaginyl-cadaveryl moiety in their molecules and their structure may be represented in a simplified way: NPTX-801E is HO-indole-Asn-Cad-Pta-Orn-Arg and NPTX-801C is HO-indole-Asn-Cad-Gly-Put-Pta-Pta.
Assuntos
Poliaminas/isolamento & purificação , Venenos de Aranha/química , Aminoácidos/análise , Animais , Brasil , Cromatografia Líquida de Alta Pressão , Peso Molecular , Poliaminas/química , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Espectrofotometria Ultravioleta , Venenos de Aranha/isolamento & purificaçãoRESUMO
A new strategy to characterize glutaminergic blocker acylpolymines stored in a spider venom with mass spectrometry is described. The crude spider venom extracts are amenable to direct MALDI mass spectrometry analysis which provides a rapid and accurate means of measuring the molecular weights of acylpolyamines without the isolation of individual samples. Compared with the previously developed mu-column HPLC/MS method, this procedure provides more efficient detection and identification of complex venom constituents. Twenty-five acylpolyamines were detected from Brazilian garden spider Nephilengys cruentata crude venom extracts by both HPLC/MS and MALDI-mass spectrometry. These acylpolyamine structures were determined by high-energy collision induced dissociation MS/MS method. Most of the compounds were classified into the previously reported generalized structures types A to D, which were found from the venom of Nephilengys borbonica. The structures of four acylpolyamines (M + H)+, m/z 623, 646, 688, and 745, which were not contained in the venom of Nephilengys borbonicare were determined to have arginine at the polyamine chain terminal and were named NPTX-622, -645, -687, and -744, respectively.