title: Strong repulsive forces between protein and oligo (ethylene glycol) self-assembled monolayers: a molecular simulation study.
abstract: Restrained molecular dynamics simulations were performed to study the interaction forces of a protein with the self-assembled monolayers (SAMs) of S(CH2)4(EG)4OH, S(CH2)11OH, and S(CH2)11CH3 in the presence of water molecules. The force-distance curves were calculated by fixing the center of mass of the protein at several separation distances from the SAM surface. Simulation results show that the relative strength of repulsive force acting on the protein is in the decreasing order of OEG-SAMs > OH-SAMs > CH3-SAMs. The force contributions from SAMs and water molecules, the structural and dynamic behavior of hydration water, and the flexibility and conformation state of SAMs were also examined to study how water structure at the interface and SAM flexibility affect the forces exerted on the protein. Results show that a tightly bound water layer adjacent to the OEG-SAMs is mainly responsible for the large repulsive hydration force.
authors.affiliation: Department of Chemical Engineering, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
authors.forename: Lingyan
authors.initials: L
authors.lastname: Li
authors.forename: Heng-Kwong
authors.initials: HK
authors.lastname: Tsao
authors.forename: Yu-Jane
authors.initials: YJ
authors.lastname: Sheng
authors.forename: Shenfu
authors.initials: S
authors.lastname: Chen
authors.forename: Shaoyi
authors.initials: S
authors.lastname: Jiang
mesh_terms: D000327:Adsorption; D001703:Biophysics / Q000379:methods*; D003198:Computer Simulation; D019855:Ethylene Glycol / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D019563:Mechanics; D008958:Models, Molecular; D008968:Molecular Conformation; D009010:Monte Carlo Method; D009113:Muramidase / Q000737:chemistry; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry; D013499:Surface Properties; D014867:Water
chemical_list: D011506:Proteins; D014867:Water; D009113:Muramidase; D019855:Ethylene Glycol