The homochirality of amino acids in living organisms is one of the great mysteries in the phenomena of life. To understand the chiral recognition of amino acids, we have used scanning tunnelling microscopy to investigate the self-assembly of molecules of the amino acid tryptophan (Trp) on Au(111). Earlier experiments showed only homochiral configurations in the self-assembly of amino acids, despite using a mixture of the two opposite enantiomers. In our study, we demonstrate that heterochiral configurations can be favored energetically when l- and d-Trp molecules are mixed to form self-assembly on the Au surface. Using density functional theory calculations, we show that the indole side chain strongly interacts with the Au surface, which reduces the system effectively to two-dimension, with chiral recognition disabled. Our study provides important insight into the recognition of the chirality of amino acid molecules in life.

生物体中氨基酸的同手性是生命现象中最大的谜团之一。为了了解氨基酸的手性识别，我们使用扫描隧道显微镜研究了氨基酸色氨酸 (Trp) 分子在 Au(111) 上的自组装。早期的实验表明，尽管使用了两种相反对映体的混合物，但氨基酸自组装中仅存在纯手性构型。在我们的研究中，我们证明，当l-和d -Trp 分子混合在 Au 表面上形成自组装时，异手性构型可以得到大力支持。使用密度泛函理论计算，我们表明吲哚侧链与金表面强烈相互作用，从而有效地将系统降低到二维，并且手性识别被禁用。我们的研究为识别生命中氨基酸分子的手性提供了重要的见解。