Venomic and antivenomic analyses of the Central American coral snake, Micrurus nigrocinctus (Elapidae)

Abstract

The proteome of the venom of Micrurus nigrocinctus (Central American coral snake) was analyzed by a “venomics” approach. Nearly 50 venom peaks were resolved by RP-HPLC, revealing a complex protein composition. Comparative analyses of venoms from individual specimens revealed that such complexity is an intrinsic feature of this species, rather than the sum of variable individual patterns of simpler composition. Proteins related to eight distinct families were identified by MS/MS de novo peptide sequencing or N-terminal sequencing: phospholipase A2 (PLA2), three-finger toxin (3FTx), l-amino acid oxidase, C-type lectin/lectin-like, metalloproteinase, serine proteinase, ohanin, and nucleotidase. PLA2s and 3FTxs are predominant, representing 48 and 38% of the venom proteins, respectively. Within 3FTxs, several isoforms of short-chain α-neurotoxins as well as muscarinic-like toxins and proteins with similarity to long-chain κ-2 bungarotoxin were identified. PLA2s are also highly diverse, and a toxicity screening showed that they mainly exert myotoxicity, although some are lethal and may contribute to the known presynaptic neurotoxicity of this venom. An antivenomic characterization of a therapeutic monospecific M. nigrocinctus equine antivenom revealed differences in immunorecognition of venom proteins that correlate with their molecular mass, with the weakest recognition observed toward 3FTxs.