一种来自巴西矛头蝮蛇毒液的催化无活性的Lys49磷脂酶A2亚型，可刺激胰腺β细胞分泌胰岛素。

A catalytically inactive Lys49 PLA2 isoform from Bothrops jararacussu venom that stimulates insulin secretion in pancreatic beta cells.

作者信息

Fagundes Fabio H R, Aparício Ricardo, dos Santos Marcelo L, Diz Filho Eduardo B S, Oliveira Simone C B, Toyama Daniela O, Toyama Marcos H

机构信息

Departamento de Bioquímica, IB, UNICAMP – SP, Campinas – Brasil.

出版信息

Protein Pept Lett. 2011 Nov;18(11):1133-9. doi: 10.2174/092986611797200940.

DOI:10.2174/092986611797200940

PMID:21707524

Abstract

A new secretory phospholipase A2 (sPLA2) isoform from Bothrops jararacussu venom (BjVIII) has been characterized by causing platelet aggregation, an absent activity in BthTx-I, Prtx-I and PrTx-II sPLA2s. According to our results, BjVIII also enhances insulin release by the pancreatic beta cells. The complete amino acid sequence of the new isoform was determined by Edman degradation and de novo peptide sequencing. These analyses showed a G35K amino acid modification for BjVIII in comparison with BthTx-I, PrTx-I and Prtx-II, a structural difference that has been related to the conflicting biological activities among BjVIII and other Lys49 sPLA2s. The whole set of evidences collected in this work indicates that, besides the C-terminal region and B-wing of PLA2, the calcium binding loop in BjVIII should be considered as an important region, involved in the pharmacological effects of Lys49-sPLA2 isoforms from the Bothrops genus.

摘要

一种来自巴西矛头蝮蛇毒液的新型分泌型磷脂酶A2（sPLA2）同工型（BjVIII）已被鉴定，它可引起血小板聚集，而这是BthTx - I、Prtx - I和Prtx - II sPLA2所没有的活性。根据我们的结果，BjVIII还能增强胰腺β细胞的胰岛素释放。通过埃德曼降解法和从头肽测序法确定了这种新同工型的完整氨基酸序列。这些分析表明，与BthTx - I、Prtx - I和Prtx - II相比，BjVIII存在G35K氨基酸修饰，这种结构差异与BjVIII和其他Lys49 sPLA2之间相互矛盾的生物学活性有关。这项工作收集的所有证据表明，除了PLA2的C末端区域和B侧翼外，BjVIII中的钙结合环也应被视为一个重要区域，它参与了来自矛头蝮属的Lys49 - sPLA2同工型的药理作用。