Abstract: A novel 13-residue peptide Mo1659 is isolated from the venom of a the cone snail, Conus monile. HPLC fractions of the venom extract yielded an intense UV absorbing fraction with a mass of 1659 Da. De novo sequencing using matrix assisted laser desorption and ionization and electrospray MS/MS methods with analysis of proteolytic fragments yielded the amino acid sequence, FHGGSWYRFPWGY-NH2(SEQ ID NO: 1), confirmed by comparison with the chemically synthesized peptide and conventional Edman sequencing. Mo1659 has an unusual sequence with a preponderance of aromatic residues and absence of apolar, aliphatic residues like Ala, Val, Len, Ile. Mo1659 has no disulfide bridges, distinguishing it from the conotoxins and bears no sequence similarity with any of the acyclic peptides isolated thus far from cone snail venoms. Electrophysiological studies on the effect of Mo 1659 on measured currents in dorsal root ganglion neurons suggest that the peptide targets non-inactivating voltage dependent potassium channels.

Abstract: A novel 13-residue peptide Mo1659 has been isolated from the venom of a vermivorous cone snail, Conus monile. HPLC fractions of the venom extract yielded an intense UV absorbing fraction with a mass of 1659 Da. De novo sequencing using both matrix assisted laser desorption and ionization and electrospray MS/MS methods together with analysis of proteolytic fragments successfully yielded the amino acid sequence, FHGGSWYRFPWGY-NH2. This was further confirmed by comparison with the chemically synthesized peptide and by conventional Edman sequencing. Mo1659 has an unusual sequence with a preponderance of aromatic residues and the absence of apolar, aliphatic residues like Ala, Val, Leu, Ile. Mo1659 has no disulfide bridges distinguishing it from the conotoxins and bears no sequence similarity with any of the acyclic peptides isolated thus far from the venom of cone snails.

Abstract: A 26 residue peptide (Am2766) with the sequence CKQAGESCDIFSQNCCVGTCAFICIE-NH2 has been isolated and purified from the venom of the molluscivorous snail, Conus amadis, collected of the southeastern coast of India. Chemical modification and mass spectrometric studies establish that Am2766 has three disulfide bridges. Cterminal amidation has been demonstrated by mass measurements on the C-terminal fragments obtained by proteolysis. Sequence alignments establish that Am2766 belongs to the ?-conotoxin family. Am2766 inhibits the decay of the sodium current in brain rNav1.2a voltage-gated Na+ channel, stably expressed in Chinese hamster ovary (CHO) cells. Unlike ?-conotoxins have previously been isolated from molluscivorous snails, Am 2766 inhibits inactivation of mammalian sodium channel.