Tough coating proteins: subtle sequence variation modulates cohesion.

TitleTough coating proteins: subtle sequence variation modulates cohesion.
Publication TypeJournal Article
Year of Publication2015
AuthorsDas, S, Miller, DR, Kaufman, Y, Rodriguez, NRMartinez, Pallaoro, A, Harrington, MJ, Gylys, M, Israelachvili, JN, Waite, JH
JournalBiomacromolecules
Volume16
Issue3
Pagination1002-8
Date Published2015 Mar 9
ISSN1526-4602
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 Fe(3+) 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 Fe(3+) 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 Fe(3+), mfp-1 (Mc) contains Dopa with two distinct Fe(3+)-binding tendencies and prefers to form intramolecular complexes with Fe(3+). In contrast, mfp-1 (Me) is better adapted to intermolecular Fe(3+) binding by Dopa. Addition of Fe(3+) 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.

DOI10.1021/bm501893y
Alternate JournalBiomacromolecules
PubMed ID25692318
PubMed Central IDPMC4514026
Grant ListR01 DE018468 / DE / NIDCR NIH HHS / United States
R01 DE018468 / DE / NIDCR NIH HHS / United States