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A novel bactericidal homodimeric PLA 2 group-I from Walterinnesia aegyptia venom.

Research paper by Abir Ben AB Bacha, Mona Awad MA Alonazi, Mohamed Solman MS Elshikh, Aida A Karray

Indexed on: 10 Jun '18Published on: 10 Jun '18Published in: International Journal of Biological Macromolecules



Abstract

A novel non-toxic phospholipase A was purified to homogeneity in a single chromatography step from the venom of Walterinnesia aegyptia, a monotypic elapid snake caught in Saudi Arabia, and its antimicrobial and hemolytic properties were evaluated as well. This enzyme, namely WaPLA, is a homodimer with an estimated molecular mass of 30 kDa, and its NH-terminal sequence exhibits a significant degree of similarity with PLA group-I. At optimal pH (8.5) and temperature (45 °C), the purified PLA exhibited a specific activity of 2100 U/mg, and it requires bile salts and Ca for its activity. However, other cations such as Cd and Hg diminished the enzyme activity remarkably, thereby suggesting that the catalytic site arrangement has an exclusive structure for Ca binding. Furthermore, WaPLA maintained almost 100% and 60% of its full activity in a pH range of 6.0-10 after 24 h incubation or after 60 min treatment at 70 °C, respectively. In the biological activity assays, WaPLA displayed potent indirectly hemolytic and antimicrobial activities that were strongly correlated. These promising findings encourage further in-depth research to understand the molecular mechanism of WaPLA's antimicrobial properties for its possible use as a potential therapeutic lead molecule for treating infections. Copyright © 2017. Published by Elsevier B.V.