All-atom molecular dynamics is the most direct method to predict the molecular-level events associated with protein-surface interactions. However, current force fields have not been validated for this application. The free energy of adsorption (?Gads) provides the most direct thermodynamic measure of the dominating events governing peptide-surface interactions. The objective of our study was to calculate ?Gads of small host-guest peptides (TGTG-X-GTGT, where T=threonine; G=glycine; and X being asparagine, aspartate, glycine, lysine, phenylalanine, threonine, tryptophan, or valine) and to compare these ?Gads values with experimental results. Simulations were performed on three types of surfaces (high-density polyethylene, poly(methyl-methacrylate), and silica glass) with explicitly represented water molecules utilizing the CHARMM force field. Simulation results indicate that corrections in non-bonded force-field parameters are necessary to provide ?Gads values that closely match the experimental data. Following force field parameter adjustment and validation, simulations can be conducted with the potential to accurately predict protein adsorption behavior.

Accurate simulation of peptide adsorption to polyethylene, poly(methyl-methacrylate), and silica surfaces using a modified CHARMM force field

243rd National Meeting (2012)

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