Rahim Abdur, Saha Pinaki, Jha Kunal Kumar, Sukumar Nagamani, Sarma Bani Kanta
Department of Chemistry, School of Natural Sciences, Shiv Nadar University, Dadri, Uttar Pradesh, 201314, India.
Nat Commun. 2017 Jul 19;8(1):78. doi: 10.1038/s41467-017-00081-x.
Carbonyl-carbonyl n→π* interactions where a lone pair (n) of the oxygen atom of a carbonyl group is delocalized over the π* orbital of a nearby carbonyl group have attracted a lot of attention in recent years due to their ability to affect the 3D structure of small molecules, polyesters, peptides, and proteins. In this paper, we report the discovery of a "reciprocal" carbonyl-carbonyl interaction with substantial back and forth n→π* and π→π* electron delocalization between neighboring carbonyl groups. We have carried out experimental studies, analyses of crystallographic databases and theoretical calculations to show the presence of this interaction in both small molecules and proteins. In proteins, these interactions are primarily found in polyproline II (PPII) helices. As PPII are the most abundant secondary structures in unfolded proteins, we propose that these local interactions may have implications in protein folding.Carbonyl-carbonyl π* non covalent interactions affect the structure and stability of small molecules and proteins. Here, the authors carry out experimental studies, analyses of crystallographic databases and theoretical calculations to describe an additional type of carbonyl-carbonyl interaction.
羰基-羰基 n→π* 相互作用是指羰基中氧原子的孤对电子（n）离域到附近羰基的 π* 轨道上，近年来，这种相互作用因其能够影响小分子、聚酯、肽和蛋白质的三维结构而备受关注。在本文中，我们报告了一种“相互”的羰基-羰基相互作用的发现，相邻羰基之间存在大量来回的 n→π* 和 π→π* 电子离域。我们进行了实验研究、晶体学数据库分析和理论计算，以证明这种相互作用在小分子和蛋白质中均存在。在蛋白质中，这些相互作用主要存在于多聚脯氨酸 II（PPII）螺旋中。由于PPII是未折叠蛋白质中最丰富的二级结构，我们认为这些局部相互作用可能对蛋白质折叠有影响。羰基-羰基 π* 非共价相互作用影响小分子和蛋白质的结构与稳定性。在此，作者进行了实验研究、晶体学数据库分析和理论计算，以描述另一种类型的羰基-羰基相互作用。
