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Abstract: Snake venom phospholipases A2 (PLA2s) are responsible for numerous pathophysiological effects in snakebites; however, their biochemical properties favour antimicrobial actions against different pathogens, thus constituting a true source of potential microbicidal agents. This study describes the isolation of a Lys49 PLA2 homologue from Lachesis muta muta venom using two chromatographic steps: size exclusion and reverse phase. The protein showed a molecular mass of 13,889 Da and was devoid of phospholipase activity on an artificial substrate. The primary structure made it possible to identify an unpublished protein from L. m. muta venom, named LmutTX, that presented high identity with other Lys49 PLA2s from bothropic venoms. Synthetic peptides designed from LmutTX were evaluated for their cytotoxic and antimicrobial activities. LmutTX was cytotoxic against C2C12 myotubes at concentrations of at least 200 μg/mL, whereas the peptides showed a low cytolytic effect. LmutTX showed antibacterial activity against Gram‐positive and Gram‐negative bacteria; however, S. aureusATCC 29213 and MRSA strains were more sensitive to the toxin's action. Synthetic peptides were tested on S. aureus, MRSA and P. aeruginosaATCC 27853 strains, showing promising results. This study describes for the first time the isolation of a Lys49 PLA2 from Lachesis snake venom and shows that peptides from specific regions of the sequence may constitute new sources of molecules with biotechnological potential. [ABSTRACT FROM AUTHOR]

Snake venom is a complex mixture of active compounds consisting of 80–90% proteins and peptides that exhibit a variety of biological actions that are not completely clarified or identified. Of these, phospholipase A 2 is one of the molecules that has shown great biotechnological potential. The objectives of this study were to isolate, biochemically and biologically characterize a Lys49 phospholipase A 2 homologue from the venom of Bothrops neuwiedi urutu . The protein was purified after two chromatographic steps, anion exchange and reverse phase. The purity and relative molecular mass were assessed by SDS-PAGE, observing a molecular weight typical of PLA 2 s, subsequently confirmed by mass spectrometry obtaining a mass of 13,733 Da. As for phospholipase activity, the PLA 2 proved to be enzymatically inactive. The analyses by Edman degradation and sequencing of the peptide fragments allowed for the identification of 108 amino acid residues; this sequence showed high identity with other phospholipases A 2 from Bothrops snake venoms, and identified this molecule as a novel PLA 2 isoform from B . neuwiedi urutu venom, called BnuTX-I. In murine models, both BnuTX-I as well as the venom induced edema and myotoxic responses. The cytotoxic effect of BnuTX-I in murine macrophages was observed at concentrations above 12 μg/mL. BnuTX-I also presented antimicrobial activity against gram-positive and negative bacterial strains, having the greatest inhibitory effect on Pseudomonas aeruginosa . The results allowed for the identification of a new myotoxin isoform with PLA 2 structure with promising biotechnological applications. [ABSTRACT FROM AUTHOR]