InterPro domain: IPR002964

An impressive property of mussels is their ability to stick to wet surfaces.Exactly how they do this is unclear, but they are known to exploit bundlesof threads, each of which has a fibrous collagenous core coated with adhesive proteins [ 1 ]. These proteins are able to displace water from a wet surface and then set to form tight junctions.The adhesive protein of Mytilus coruscus (Sea mussel) contains 848 amino acids, including a 20-residue signal peptide, a 21-residue non-repetitive linker and a repetitive domain that constitutes the bulk of the protein. The representative repeat motif of this domain, YKPK(I/P)(S/T)YPP(T/S), is similar to that of Mytilus galloprovincialis (Mediterranean mussel). The codon usage patterns for the same amino acids differ in different positions of the decapeptide motif[ 2 , 2 ]. Almost identical nucleotide sequences appear several times in the repetitive region, suggesting that mussel adhesive protein genes have evolved through repeat duplication [ 3 ]. The repeat motif is reminiscent of repeat units found in extensins, a group of plant proteins involved in the strengthening of the cell wall in response to mechanical stress.

1. The adhesive protein cDNA of Mytilus galloprovincialis encodes decapeptide repeats but no hexapeptide motif. Biol. Bull. 186, 349-55
2. Adhesive protein cDNA sequence of the mussel Mytilus coruscus and its evolutionary implications. J. Mol. Evol. 43, 348-56