Myotoxic phospholipases A₂ isolated from Bothrops brazili

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• 作者：Tassia R. Costa ; Danilo L. Menaldo ; Clayton Z. Oliveira ; Norival A. Santos-Filho ; Sabrina S. Teixeira ; Auro Nomizo ; André ; L. Fuly ; Marta C. Monteiro ; Bibiana M. de Souza ; Má ; rio S. Palma ; Rod
• 关键词：Cytotoxicity ; Microbicide ; Bothrops brazili ; Synthetic peptides ; Phospholipases A₂ ; Myotoxins ; Snake venom
• 刊名：Peptides
• 出版年：2008
• 出版时间：October 2008
• 年：2008
• 卷：29
• 期：10
• 页码：1645-1656
• 全文大小：1771 K

文摘

This paper reports the purification and biochemical/pharmacological characterization of two myotoxic phospholipases A₂ (PLA₂s) from Bothrops brazili venom, a native snake from Brazil. Both myotoxins (MTX-I and II) were purified by a single chromatographic step on a CM-Sepharose ion-exchange column up to a high purity level, showing M_r  14,000 for the monomer and 28,000 Da for the dimer. The N-terminal and internal peptide amino acid sequences showed similarity with other myotoxic PLA₂s from snake venoms, MTX-I belonging to Asp49 PLA₂ class, enzymatically active, and MTX-II to Lys49 PLA₂s, catalytically inactive. Treatment of MTX-I with BPB and EDTA reduced drastically its PLA₂ and anticoagulant activities, corroborating the importance of residue His48 and Ca²⁺ ions for the enzymatic catalysis. Both PLA₂s induced myotoxic activity and dose–time dependent edema similar to other isolated snake venom toxins from Bothrops and Crotalus genus. The results also demonstrated that MTXs and cationic synthetic peptides derived from their 115–129 C-terminal region displayed cytotoxic activity on human T-cell leukemia (JURKAT) lines and microbicidal effects against Escherichia coli, Candida albicans and Leishmania sp. Thus, these PLA₂ proteins and C-terminal synthetic peptides present multifunctional properties that might be of interest in the development of therapeutic strategies against parasites, bacteria and cancer.