The adhesive protein of Choromytilus chorus (Molina, 1782) and Aulacomya ater (Molina, 1782): a proline-rich and a glycine-rich polyphenolic protein

The adhesive polyphenolic proteins from Aulacomya ater and Choromytilus cho rus with apparent molecular masses of 135 000 and 105 000, respectively, we re digested with trypsin and the peptides produced resolved by reversed pha se liquid chromatography. About 5 and 12 major peptides were obtained from the protein of A. ater and C. chorus, respectively. The major peptides were purified by reverse-phase chromatography and the amino acid sequence indic ates that both polyphenolic proteins consisted of repeated sequence motifs in their primary structure. The major peptides of A. ater contain seven ami no acids corresponding to the consensus sequence AGYGGXK, whereas the tyros ine was always found as 3,4-dihydroxyphenylalanine (Dopa), the X residue in position 6 was either valine, leucine or isoleucine, and the carboxy termi nal was either lysine or hydroxylysine. On the other hand, the major peptid es of C. chorus ranged in size from 6 to 21 amino acids and the majority co rrespond to the consensus sequence AKPSKYPTGYKPPVK. Both proteins differ ma rkedly in the sequence of their tryptic peptides, but they share the common characteristics of other adhesive proteins in having a tandem sequence rep eat in their primary structure. (C) 2000 Elsevier Science B.V. All rights r eserved.