title: Hydration Dynamics of a Peripheral Membrane Protein.
abstract: Water dynamics in the hydration shell of the peripheral membrane protein annexin B12 were studied using MD simulations and Overhauser DNP-enhanced NMR. We show that retardation of water motions near phospholipid bilayers is extended by the presence of a membrane-bound protein, up to around 10 Å above that protein. Near the membrane surface, electrostatic interactions with the lipid head groups strongly slow down water dynamics, whereas protein-induced water retardation is weaker and dominates only at distances beyond 10 Å from the membrane surface. The results can be understood from a simple model based on additive contributions from the membrane and the protein to the activation free energy barriers of water diffusion next to the biomolecular surfaces. Furthermore, analysis of the intermolecular vibrations of the water network reveals that retarded water motions near the membrane shift the vibrational modes to higher frequencies, which we used to identify an entropy gradient from the membrane surface toward the bulk water. Our results have implications for processes that take place at lipid membrane surfaces, including molecular recognition, binding, and protein-protein interactions.
authors.affiliation: Center for Theoretical Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-University , 44780 Bochum, Germany.
authors.forename: Olivier
authors.initials: O
authors.lastname: Fisette
authors.affiliation: Center for Theoretical Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-University , 44780 Bochum, Germany.|Max-Planck Institut für Kohlenforschung , 45470 Mülheim an der Ruhr, Germany.
authors.forename: Christopher
authors.initials: C
authors.lastname: Päslack
authors.affiliation: Department of Chemistry and Biochemistry and Department of Chemical Engineering, University of California, Santa Barbara , Santa Barbara, California 93106, United States.
authors.forename: Ryan
authors.initials: R
authors.lastname: Barnes
authors.affiliation: Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: J Mario
authors.initials: JM
authors.lastname: Isas
authors.affiliation: Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Ralf
authors.initials: R
authors.lastname: Langen
authors.affiliation: Max-Planck Institut für Kohlenforschung , 45470 Mülheim an der Ruhr, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Heyden
authors.affiliation: Department of Chemistry and Biochemistry and Department of Chemical Engineering, University of California, Santa Barbara , Santa Barbara, California 93106, United States.
authors.forename: Songi
authors.initials: S
authors.lastname: Han
authors.affiliation: Center for Theoretical Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-University , 44780 Bochum, Germany.
authors.forename: Lars V
authors.initials: LV
authors.lastname: Schäfer
mesh_terms: D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D004058:Diffusion; D019277:Entropy; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D056004:Molecular Dynamics Simulation; D013499:Surface Properties; D014867:Water / Q000378:metabolism
chemical_list: D008051:Lipid Bilayers; D008565:Membrane Proteins; D014867:Water