title: Molecular interactions of mussel protective coating protein, mcfp-1, from Mytilus californianus.
abstract: Protective coating of the byssus of mussels (Mytilus sp.) has been suggested as a new paradigm of medical coating due to its high extensibility and hardness co-existence without their mutual detriment. The only known biomacromolecule in the extensible and tough coating on the byssus is mussel foot protein-1 (mfp-1), which is made up with positively charged residues (~20 mol%) and lack of negatively charged residues. Here, adhesion and molecular interaction mechanisms of Mytilus californianus foot protein-1 (mcfp-1) from California blue mussel were investigated using a surface forces apparatus (SFA) in buffer solutions of different ionic concentrations (0.2-0.7 M) and pHs (3.0-5.5). Strong and reversible cohesion between opposed positively charged mcfp-1 films was measured in 0.1 M sodium acetate buffer with 0.1 M KNO(3). Cohesion of mcfp-1 was gradually reduced with increasing the ionic strength, but was not changed with pH variations. Oxidation of 3,4-dihydroxyphenylalanine (DOPA) residues of mcfp-1, a key residue for adhesive and coating proteins of mussel, didn't change the cohesion strength of mcfp-1 films, but the addition of chemicals with aromatic groups (i.e., aspirin and 4-methylcatechol) increased the cohesion. These results suggest that the cohesion of mcfp-1 films is mainly mediated by cation-π interactions between the positively charged residues and benzene rings of DOPA and other aromatic amino acids (~20 mol% of total amino acids of mcfp-1), and π-π interactions between the phenyl groups in mcfp-1. The adhesion mechanism obtained for the mcfp-1 proteins provides important insight into the design and development of functional biomaterials and coatings mimicking the extensible and robust mussel cuticle coating.
authors.affiliation: Chemical and Materials Engineering, University of Alberta, Edmonton, AB, Canada T6G 2V4.
authors.forename: Qingye
authors.initials: Q
authors.lastname: Lu
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Hwang
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Hongbo
authors.initials: H
authors.lastname: Zeng
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000494:pharmacology; D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D049872:Bivalvia / Q000378:metabolism*; D002021:Buffers; D002244:Carbon / Q000737:chemistry; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D007477:Ions; D008956:Models, Chemical; D049878:Mytilus / Q000378:metabolism*; D011506:Proteins / Q000737:chemistry*; D055672:Static Electricity; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D000596:Amino Acids; D001672:Biocompatible Materials; D002021:Buffers; D007477:Ions; D011506:Proteins; D015102:3,4-Dihydroxyphenylacetic Acid; D002244:Carbon