Proteomic analysis of the venom from the fish eating coral snake Micrurus surinamensis: Novel toxins, their function and phylogeny

Abstract

The protein composition of the soluble venom from the South American fish-eating coral snake Micrurus surinamensis surinamensis, here abbreviated M. surinamensis, was separated by RP-HPLC and 2-DE, and their components were analyzed by automatic Edman degradation, MALDI-TOF and ESI-MS/MS. Approximately 100 different molecules were identified. Sixty-two components possess molecular masses between 6 and 8 kDa, are basically charged molecules, among which are cytotoxins and neurotoxins lethal to fish (Brachidanios rerio). Six new toxins (abbreviated Ms1-Ms5 and Ms11) were fully sequenced. Amino acid sequences similar to the enzymes phospholipase A2 and amino acid oxidase were identified. Over 20 additional peptides were identified by sequencing minor components of the HPLC separation and from 2-DE gels. A functional assessment of the physiological activity of the six toxins was also performed by patch clamp using muscular nicotinic acetylcholine receptor assays. Variable degrees of blockade were observed, most of them reversible. The structural and functional data obtained were used for phylogenetic analysis, providing information on some evolutionary aspects of the venom components of this snake. This contribution increases by a factor of two the total number of alpha-neurotoxins sequenced from the Micrurus genus in currently available literature.