Molecular modeling of interactions between L-lysine and a hydroxylated quartz surface

The static and dynamical properties of L-lysine adsorbed onto a hydroxylated quartz surface were modeled by using semiempirical quantum mechanics and force field techniques. Both semiempirical and force field calculations indicate that a strong interaction occurs between the c-protonated amino group of L-lysine with the surface. Furthermore, the amino acid molecule has a preferred end-on orientation, with the epsilon-protonated amino group pointing toward the surface. The statistical analysis of the system trajectories reveals that the relatively ordered water-shell structure of the amino acid molecule in the "bulk" solution is broken when the molecule approaches the surface because of the reciprocal perturbation of the molecule and surface solvation shells.