Multiple bromotryptophan and y-carboxyglutamate residues in a Conus peptide

A novel peptide was purified from Conus textile venom which caused hyperactivity in mice. The 31-amino acid peptide has six residues with unusual post-translational modifications: four y-carboxyglutamates and two brominated tryptophan residues. This peptide, which we have designated the dibromorunning peptide, is the first known gene product with multiple bromotryptophan residues. We discuss the apparent non-random association of y-carboxyglutamate and bromotryptophan in Conus peptides.