Isolation and characterization of five novel mini-M conotoxins from the venom of mollusk-hunter snail Conus bandanus

Objective:To determine the new M-superfamily conotoxins from molluscivorous snail Conus bandanus in Vietnam.Methods:Conus bandanus venom was fractionated and purified on HPLC system with an analytical reversed-phase C18 column in order to screen small conotoxins.The primary structure of peptide was analyzed by matrix-assisted laser desorption/ionization time of flight tandem mass spectrometry using collision-induced dissociation and confirmed by Edman’s degradation method.Results:Five new conotoxins were biochemically characterized from the crude venom of the mollusk-hunting cone snail Conus bandanus,which were collected at Ke Ga reef of the Nha Trang Bay(Vietnam).Each conotoxin had 15 or 16 amino acid residues and shared the same characteristic cysteine framework V as–CC–C–C–CC–.They were termed as Bn3 b,Bn3 c,Bn3 d,Bn3 e and Bn3 f following the conotoxins nomenclature.Conclusions:The conotoxins Bn3 b,Bn3 e,and Bn3 f are categorized in the mini-M conotoxins of the M1 branch,while conotoxins Bn3 c and Bn3 d are categorized in the mini-M conotoxins of the M2 branch.The homological analysis reveals that these conotoxins could serve as promising probe compounds for voltage-gated sodium channels.