AVS 51st International Symposium
    Biomaterial Interfaces Monday Sessions
       Session BI-MoA

Paper BI-MoA5
Molecular Dynamics Simulation of the @gamma@ Chain Fragment of Fibrinogen on Functionalized SAM Surfaces

Monday, November 15, 2004, 3:20 pm, Room 210D

Session: Protein-Surface Interactions
Presenter: R.A. Latour, Clemson University
Authors: M. Agashe, Clemson University
S.J. Stuart, Clemson University
R.A. Latour, Clemson University
Correspondent: Click to Email
Protein adsorption to biomaterials surfaces is a primary governing factor of biocompatibility. While much has been learned, the molecular mechanisms involved in adsorption behavior are not understood. Empirical force field based molecular simulation methods provide an excellent approach to theoretically investigate the molecular behavior of proteins as they adsorb to surfaces. In this research, molecular dynamics simulations were conducted to investigate the adsorption behavior of a 30kDa C-terminus fragment of the @gamma@ chain of fibrinogen (Fg) as a function of surface chemistry. Simulations were conducted using the GROMACS program and force field. The surfaces were modeled to represent Au-alkanethiol self-assembled monolayers (SAMs) with 5 surface functionalities: CH3, OH, NH2, COOH, and PEG. The model system consisted of Fg in saline (explicit water with Na+ and Cl- ions) positioned over a SAM surface. Systems were contained within a 105Å x 107Å base x 80Å high simulation cell with periodic boundary conditions. 5ns simulations were performed and the effects of adsorption on Fg were analyzed. The results predict that only minor changes in Fg conformation occur during this time frame, however, Fg was observed to undergo large surface-dependent rotational and translational motions, suggesting faster kinetics for reorientation than unfolding. Although contingent on the accuracy of the GROMACS force field, which has not yet been validated for this application, these results have profound implications for surface design because they suggest that surface chemistry should be an effective means to control the orientation of adsorbed proteins.