Institute for Frontier Materials, Deakin University , Geelong, Victoria 3216, Australia.
Langmuir. 2013 Oct 29;29(43):13217-29. doi: 10.1021/la402839q. Epub 2013 Oct 14.
The molecular simulation of biomolecules adsorbed at noble metal interfaces can assist in the development of bionanotechnology applications. In line with advances in polarizable force fields for adsorption at aqueous gold interfaces, there is scope for developing a similar force field for silver. One way to accomplish this is via the generation of in vacuo adsorption energies calculated using first-principles approaches for a wide range of different but biologically relevant small molecules, including water. Here, we present such first-principles data for a comprehensive range of bio-organic molecules obtained from plane-wave density functional theory calculations using the vdW-DF functional. As reported previously for the gold force field, GolP-CHARMM (Wright, L. B.; Rodger, P. M.; Corni, S.; Walsh, T. R. GolP-CHARMM: first-principles based force-fields for the interaction of proteins with Au(111) and Au(100). J. Chem. Theory Comput. 2013, 9, 1616-1630), we have used these data to construct a a new force field, AgP-CHARMM, suitable for the simulation of biomolecules at the aqueous Ag(111) and Ag(100) interfaces. This force field is derived to be consistent with GolP-CHARMM such that adsorption on Ag and Au can be compared on an equal footing. Our force fields are used to evaluate the water overlayer stability on both silver and gold, finding good agreement with known behaviors. We also calculate and compare the structuring (spatial and orientational) of liquid water adsorbed at both silver and gold. Finally, we report the adsorption free energy of a range of amino acids at both the Au(111) and Ag(111) aqueous interfaces, calculated using metadynamics. Stronger adsorption on gold was noted in most cases, with the exception being the carboxylate group present in aspartic acid. Our findings also indicate differences in the binding free energy profile between silver and gold for some amino acids, notably for His and Arg. Our analysis suggests that the relatively stronger structuring of the first water layer on silver, relative to gold, could give rise to these differences.
生物分子在贵金属界面上的吸附的分子模拟有助于推动生物纳米技术应用的发展。随着针对水合金界面吸附的极化力场的发展，开发类似的银力场成为可能。一种方法是通过使用第一性原理方法计算广泛的不同但具有生物学相关性的小分子（包括水）在真空中的吸附能来实现这一点。在这里，我们展示了使用基于 vdW-DF 泛函的平面波密度泛函理论计算获得的各种生物有机分子的此类第一性原理数据。正如之前报道的金力场那样，GolP-CHARMM（Wright，LB；Rodger，PM；Corni，S.；Walsh，TR GolP-CHARMM：基于第一性原理的蛋白质与 Au（111）和 Au（100）相互作用的力场。J.Chem.Theory Comput.2013,9,1616-1630），我们使用这些数据构建了一个新的力场，AgP-CHARMM，适用于水合银（111）和银（100）界面上生物分子的模拟。该力场的推导与 GolP-CHARMM 一致，以便可以平等地比较银和金上的吸附。我们的力场用于评估水在银和金上的覆盖层稳定性，发现与已知行为吻合良好。我们还计算并比较了液体水在银和金上的结构（空间和取向）。最后，我们使用元动力学计算并比较了一系列氨基酸在 Au（111）和 Ag（111）水合界面上的吸附自由能。在大多数情况下，金的吸附更强，除了天冬氨酸中的羧酸基团。我们的发现还表明，对于某些氨基酸，例如 His 和 Arg，银和金之间的结合自由能分布存在差异。我们的分析表明，与金相比，银上第一层水的相对较强结构可能导致了这些差异。
