Abstract

Bothorps atrox is responsible for most of the ophidism cases in Peru. As part of the envenoming, myotoxicity is one of the most recurrent and destructive effects. In this study, a myotoxin, named BaMtx, was purified from B. atrox venom to elucidate its biological, immunological, and molecular characteristics. BaMtx was purified using CM-Sephadex-C-25 ion-exchange resin and SDS-PAGE analysis showed a unique protein band of 13 kDa or 24 kDa under reducing or non-reducing conditions, respectively. cDNA sequence codified a 122-aa mature protein with high homology with other Lys49-PLA(2)s; modeled structure showed a N-terminal helix, a beta-wing region, and a C-terminal random coil. This protein has a poor phospholipase A2 enzymatic activity. BaMtx has myotoxic (DMM = 12.30 +/- 0.95 mu g) and edema-forming (DEM = 26.00 +/- 1.15 mu g) activities. Rabbit immunization with purified enzyme produced anti-BaMtx antibodies that reduced 50.28 +/- 10.15% of myotoxic activity and showed significant cross-reactivity against B. brazili and B pictus venoms. On the other hand, BaMtx exhibits mild anti-proliferative and anti-migratory effects on breast cancer cells, affecting the ROS and NADH levels, which may reduce mitochondrial respiration. These results contribute to the understanding of B. atrox Lys49PLA2 effects and establish the anticancer potential de BaMtx.