Polyphosphoprotein from the adhesive pads of Mytilus edulis

Biochemistry. 2001 Mar 6;40(9):2887-93. doi: 10.1021/bi002718x.

Abstract

Achieving a satisfactory biochemical explanation for the opportunistic underwater adhesion of marine invertebrates such as mussels and barnacles requires a detailed characterization of proteins extracted from holdfast structures produced by these organisms. Mefp-5 is an adhesive protein derived from the foot of the common mussel, Mytilus edulis, and deposited into the byssal attachment pads. Purification and primary structure of mefp-5 was determined by peptide mapping and cDNA sequencing. The protein is 74 residues long and has a mass of about 9500 Da. Mefp-5 composition shows a strong amino acid bias: aromatic amino acids, lysine, and glycine represent 65 mol % of the composition. More than a third of all the residues in the protein are posttranslationally modified by hydroxylation or phosphorylation. The conversion of tyrosine to 3, 4-dihydroxyphenyl-L-alanine (DOPA) and serine to O-phosphoserine accounts for the hydroxylation and phosphorylation, respectively. Neither modification is complete since variations in the extent of phosphorylation and hydroxylation can be detected by mass spectrometry. More than 75% of the DOPA is adjacent to basic residues, e.g., Lys-DOPA and DOPA-Lys. Phosphoserine occurs in sequences strikingly reminiscent of acidic mineral-binding motifs that appear in statherin, osteopontin, and others. This may be an adaptation for adhesion to the most common substrata for mussels, i.e., calcareous materials.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Amino Acids / analysis
  • Animals
  • Base Sequence
  • Bivalvia / chemistry*
  • Bivalvia / genetics
  • Chromatography, High Pressure Liquid
  • DNA, Complementary / chemistry
  • DNA, Complementary / isolation & purification
  • Molecular Sequence Data
  • Phosphoproteins / chemistry*
  • Phosphoproteins / genetics
  • Phosphoproteins / isolation & purification
  • Polymerase Chain Reaction
  • Proteins / chemistry*
  • Proteins / genetics
  • Proteins / isolation & purification
  • Sequence Analysis, Protein
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Substances

  • Amino Acids
  • DNA, Complementary
  • Phosphoproteins
  • Proteins
  • adhesive protein, mussel

Associated data

  • GENBANK/AF333078