Comparative proteomics and subtyping of venom phospholipases A 2 and disintegrins of Protobothrops pit vipers

Abstract

To explore the venom diversity and systematics of pit vipers under the genus Protobothrops, the venom phospholipases A 2 (PLA 2s) of P. mangshanensis, P. elegans and P. tokarensis were purified and characterized for the first time. The results were compared with the corresponding venom data of other co-generic species including P. mucrosquamatus, P. flavoviridis and P. jerdonii. Based on sequence features at the N-terminal regions, we identified five PLA 2 subtypes, i.e., the Asp49-PLA 2s with N6, E6 or R6 substitution and the Lys49-PLA 2. However, not all subtypes were expressed in each of the species. Venom N6-PLA 2s from P. mangshanensis and P. tokarensis venom were weakly neurotoxic toward chick biventer cervicis tissue preparations. The venoms of P. tokarensis and P. flavoviridis contained identical PLA 2 isoforms. In most Protobothrop disintegrins, sequences flanking the RGD-motif are conserved. Phylogenetic analyses based on amino acid sequences of both families of the acidic PLA 2s and the disintegrins clarify that these species could belong to a monophyletic group.