Tough Coating Proteins: Subtle Sequence Variation Modulates Cohesion

Saurabh Das, Dusty R. Miller, Yair Kaufman, Nadine R. Martinez Rodriguez, Alessia Pallaoro, Matthew J. Harrington, Maryte Gylys, Jacob N. Israelachvili, J. Herbert Waite

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Mussel foot protein-1 (mfp-1) is an essential constituent of the protective cuticle covering all exposed portions of the byssus (plaque and the thread) that marine mussels use to attach to intertidal rocks. The reversible complexation of Fe3+ by the 3,4-dihydroxyphenylalanine (Dopa) side chains in mfp-1 in Mytilus californianus cuticle is responsible for its high extensibility (120%) as well as its stiffness (2 GPa) due to the formation of sacrificial bonds that help to dissipate energy and avoid accumulation of stresses in the material. We have investigated the interactions between Fe3+ and mfp-1 from two mussel species, M. californianus (Mc) and M. edulis (Me), using both surface sensitive and solution phase techniques. Our results show that although mfp-1 homologues from both species bind Fe3+, mfp-1 (Mc) contains Dopa with two distinct Fe3+-binding tendencies and prefers to form intramolecular complexes with Fe3+. In contrast, mfp-1 (Me) is better adapted to intermolecular Fe3+ binding by Dopa. Addition of Fe3+ did not significantly increase the cohesion energy between the mfp-1 (Mc) films at pH 5.5. However, iron appears to stabilize the cohesive bridging of mfp-1 (Mc) films at the physiologically relevant pH of 7.5, where most other mfps lose their ability to adhere reversibly. Understanding the molecular mechanisms underpinning the capacity of M. californianus cuticle to withstand twice the strain of M. edulis cuticle is important for engineering of tunable strain tolerant composite coatings for biomedical applications. (Chemical Equation Presented).

Original languageEnglish
Pages (from-to)1002-1008
Number of pages7
JournalBiomacromolecules
Volume16
Issue number3
DOIs
StatePublished - 9 Mar 2015
Externally publishedYes

ASJC Scopus subject areas

  • Bioengineering
  • Biomaterials
  • Polymers and Plastics
  • Materials Chemistry

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