Buccalin-Like and Myomodulin-Like Peptides in the Stomatogastric Ganglion of the Crab Cancer Borealis

The buccalins and myomodulins are families of peptides originally isolated and purified from the accessory radula closer (ARC) nerve–muscle system of the marine mollusc Aplysia californica (Cropper et al. 1987a,b, 1988). In A. californica, the buccalin family consists of 19 related peptides (buccalins A–S), each of which exhibits a homologous carboxyl terminal sequence, Phe-X-Gly-Gly-X-NH2 (Cropper et al. 1988; Miller et al. 1993a). A cDNA clone encoding a buccalin precursor polypeptide has recently been isolated (Miller et al. 1993a). This buccalin gene appears to be present as a single copy in the A. californica genome. The precursor peptide predicted from this gene encodes all 19 buccalin-like molecules, several in multiple copies.