A protonated L-cysteine adsorption on gold surface: A molecular dynamics study

Abstract

The adsorption of protonated L -cysteine onto Au(111) surface was studied via molecular dynamics method. The detailed examination of trajectories reveals that a couple of picoseconds need to be strongly adsorbed at the gold surface via L -cysteine's sulfur and oxygen atoms. The average distances of L -cysteine's adsorbed sulfur and oxygen from gold plane are ~2.7 Å and ~3.2 Å, correspondingly. We found that the adsorption of L -cysteine takes place preferentially at bridge site with possibility of ~82%. Discussing the conformation features of protonated L -cysteine, we consider that the most stable conformation of protonated L -cysteine is "reverse boat" position, where sulfur and oxygen pointed down to the gold surface, while the amino group is far from the gold surface.