A novel omega conotoxin from the venom of Conus musicus: Isolation, characterization and chemical synthesis

Abstract

A novel conotoxin belonging to the \'four-loop\' structural class has been isolated from the venom of the vermivorous cone snail Conus musicus. It was identified using a chemical-directed strategy based largely on mass spectrometric techniques. The new toxin consists of 26 amino-acid residues and contains three disulfide bonds. The amino-acid sequence was determined by Edman analysis as CKGKGSOCSOTMYNCCRTGCLSGKCT where O = 4-trans-L-hydroxyproline. The sequence of new toxin was further verified by chemical synthesis and coelution studies with native material. New Conotoxin has a six cysteine/four-loop structural framework common to many peptides from Conus venoms including the ω-, δ- and K-conotoxins. However, these new toxin displays sequence homology with these well-characterized pharmacological classes of peptides. This new toxin and other conotoxins share several biochemical features and represent a distinct subgroup of the four-loop conotoxins.

Keywords: conotoxin, mass spectrometry, ion channel, amino-acid sequence, peptide synthesis.

CaJEB Vol. 3 (2) 2007: pp.61-69