Peptide Length and Dopa Determine Iron-Mediated Cohesion of Mussel Foot Proteins.

Das, Saurabh; Rodriguez, Nadine R. Martinez; Wei, Wei; Waite, J. Herbert; Israelachvili, Jacob N.

Mussel adhesion to mineral surfaces is widely attributed to 3,4-dihydroxyphenylalanine (Dopa) functionalities in the mussel foot proteins (mfps). Several mfps, however, show a broad range (30%-100%) of tyrosine (Tyr) to Dopa conversion suggesting that Dopa is not the only desirable outcome for adhesion. Here, a partial recombinant construct of mussel foot protein-1 (rmfp-1) and short decapeptide dimers with and without Dopa are used and both their cohesive and adhesive properties on mica are assessed using a surface forces apparatus. Our results demonstrate that at low pH, both the unmodified and Dopa-containing rmfp-1s show similar energies for adhesion to mica and self-self-interaction. Cohesion between two Dopa-containing rmfp-1 surfaces can be doubled by Fe3+ chelation, but remains unchanged with unmodified rmfp-1. At the same low pH, the Dopa-modified short decapeptide dimer did not show any change in cohesive interactions even with Fe3+. The results suggest that the most probable intermolecular interactions are those arising from electrostatic (i.e., cation-π) and hydrophobic interactions. It is also shown that Dopa in a peptide sequence does not by itself mediate Fe3+ bridging interactions between peptide films: peptide length is a crucial enabling factor.

DOPA; TYROSINE; ADHESION; MICA; ELECTROSTATIC interaction; HYDROPHOBIC interactions

Advanced Functional Materials, 2015, Vol 25, Issue 36, p5840

1616-301X

Academic Journal

10.1002/adfm.201502256