title: Surface force measurements and simulations of mussel-derived peptide adhesives on wet organic surfaces.
abstract: Translating sticky biological molecules-such as mussel foot proteins (MFPs)-into synthetic, cost-effective underwater adhesives with adjustable nano- and macroscale characteristics requires an intimate understanding of the glue's molecular interactions. To help facilitate the next generation of aqueous adhesives, we performed a combination of surface forces apparatus (SFA) measurements and replica-exchange molecular dynamics (REMD) simulations on a synthetic, easy to prepare, Dopa-containing peptide (MFP-3s peptide), which adheres to organic surfaces just as effectively as its wild-type protein analog. Experiments and simulations both show significant differences in peptide adsorption on CH3-terminated (hydrophobic) and OH-terminated (hydrophilic) self-assembled monolayers (SAMs), where adsorption is strongest on hydrophobic SAMs because of orientationally specific interactions with Dopa. Additional umbrella-sampling simulations yield free-energy profiles that quantitatively agree with SFA measurements and are used to extract the adhesive properties of individual amino acids within the context of MFP-3s peptide adhesion, revealing a delicate balance between van der Waals, hydrophobic, and electrostatic forces.
authors.affiliation: Department of Physics, University of California, Santa Barbara, CA 93106; Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106;
authors.forename: Zachary A
authors.initials: ZA
authors.lastname: Levine
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, CA 93106;
authors.forename: Michael V
authors.initials: MV
authors.lastname: Rapp
authors.affiliation: Materials Research Laboratory, University of California, Santa Barbara, CA 93106;
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, CA 93106;
authors.forename: Ryan Gotchy
authors.initials: RG
authors.lastname: Mullen
authors.affiliation: Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028;
authors.forename: Chun
authors.initials: C
authors.lastname: Wu
authors.affiliation: Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA 18015;
authors.forename: Gül H
authors.initials: GH
authors.lastname: Zerze
authors.affiliation: Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA 18015;
authors.forename: Jeetain
authors.initials: J
authors.lastname: Mittal
authors.affiliation: Materials Research Laboratory, University of California, Santa Barbara, CA 93106; Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, CA 93106.
authors.forename: J Herbert
authors.initials: JH
authors.lastname: Waite
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, CA 93106; Materials Research Laboratory, University of California, Santa Barbara, CA 93106; jacob@engineering.ucsb.edu shea@chem.ucsb.edu.
authors.forename: Jacob N
authors.initials: JN
authors.lastname: Israelachvili
authors.affiliation: Department of Physics, University of California, Santa Barbara, CA 93106; Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106; jacob@engineering.ucsb.edu shea@chem.ucsb.edu.
authors.forename: Joan-Emma
authors.initials: JE
authors.lastname: Shea
mesh_terms: D000269:Adhesives / Q000737:chemistry*; D000818:Animals; D049872:Bivalvia / Q000737:chemistry*; D008956:Models, Chemical; D010455:Peptides / Q000737:chemistry*; D017155:Wettability
chemical_list: D000269:Adhesives; D010455:Peptides
keywords: molecular dynamics simulations; mussel foot proteins; protein folding; self-assembled monolayers; surface forces apparatus