论文标题
金属表面柔性氨基酸的构象空间
The Conformational Space of a Flexible Amino Acid at Metallic Surfaces
论文作者
论文摘要
在与技术应用相关的无机材料和生物材料之间的界面中，结构确定的一般挑战因生物有机组件，化学键合和界面上的电荷重排而加剧。在本文中，我们研究了一个化学复杂的构建块，即精氨酸（ARG）氨基酸与Cu，Ag和Au（111）表面相连。我们通过构建和分析使用PBE功能（包括筛选的成对范德华的相互作用）进行优化的数千个结构的数据库来研究环境如何改变该氨基酸的可及构象空间。当与金属表面接触时，ARG的可访问空间会大大降低，而与气相相比，ARG-H $^+$的一个可访问空间会增加。这是通过ARG和表面之间的牢固键的形成，以及在吸附时对Arg-H $^+$的缺失和指控筛选来解释的。我们还观察到氨基酸与金属表面的质子化依赖性立体选择性结合：Arg adsorbs具有手性c $_α$ h中心，将H远离表面的H中心，而Arg-H $^+$ adsorbs则指向表面。
In interfaces between inorganic and biological materials relevant for technological applications, the general challenge of structure determination is exacerbated by the high flexibility of bioorganic components, chemical bonding, and charge rearrangement at the interface. In this paper, we investigate a chemically complex building block, namely, the arginine (Arg) amino-acid interfaced with Cu, Ag and Au (111) surfaces. We investigate how the environment changes the accessible conformational space of this amino acid, by building and analyzing a database of thousands of structures optimized with the PBE functional including screened pairwise van der Waals interactions. When in contact with metallic surfaces, the accessible space for Arg is dramatically reduced, while the one for Arg-H$^+$ is instead increased if compared to the gas-phase. This is explained by the formation of strong bonds between Arg and the surfaces and by their absence and charge screening on Arg-H$^+$ upon adsorption. We also observe protonation-dependent stereoselective binding of the amino acid to the metal surfaces: Arg adsorbs with its chiral C$_α$H center pointing H away from the surfaces while Arg-H$^+$ adsorbs with H pointing toward the surface.
