Pérez-Mellor Ariel, Zehnacker Anne
Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS and Univ Paris-Sud, Université Paris-Saclay, Orsay, France.
Chirality. 2017 Feb;29(2):89-96. doi: 10.1002/chir.22674. Epub 2017 Jan 12.
The diastereomer diketopiperazine (DKP) peptides built on phenylalanine, namely, cyclo diphenylalanine LPhe-LPhe and LPhe-DPhe, were studied in the solid phase by vibrational circular dichroism (VCD) coupled to quantum chemical calculations. The unit structure of cyclo LPhe-LPhe in KBr pellets is a dimer bridged by two strong NH…O hydrogen bonds. The intense bisignate signature in the CO stretch region is interpreted in terms of two contributions arising from the free COs of the dimer and the antisymmetrical combination of the bound COs. In contrast, cyclo LPhe-DPhe shows no VCD signal in relation to its symmetric nature.
研究了基于苯丙氨酸构建的非对映体二酮哌嗪（DKP）肽，即环二苯丙氨酸LPhe-LPhe和LPhe-DPhe，通过将振动圆二色性（VCD）与量子化学计算相结合，在固相中对其进行了研究。KBr压片中环LPhe-LPhe的单元结构是由两个强NH…O氢键桥连的二聚体。在CO伸缩区域强烈的双符号特征是根据二聚体的游离CO以及结合CO的反对称组合产生的两种贡献来解释的。相比之下，环LPhe-DPhe由于其对称性质而没有显示出VCD信号。
