Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie Street, Ottawa, Ontario, Canada.
Current address: US Department of Energy, Ames Laboratory, 213 Spedding Hall, Ames, IA, 50011, USA.
Angew Chem Int Ed Engl. 2017 Jun 19;56(26):7564-7567. doi: 10.1002/anie.201702626. Epub 2017 May 22.
Protein structure and function is dependent on myriad noncovalent interactions. Direct detection and characterization of these weak interactions in large biomolecules, such as proteins, is experimentally challenging. Herein, we report the first observation and measurement of long-range "through-space" scalar couplings between methyl and backbone carbonyl groups in proteins. These J couplings are indicative of the presence of noncovalent C-H⋅⋅⋅π hydrogen-bond-like interactions involving the amide π network. Experimentally detected scalar couplings were corroborated by a natural bond orbital analysis, which revealed the orbital nature of the interaction and the origins of the through-space J couplings. The experimental observation of this type of CH⋅⋅⋅π interaction adds a new dimension to the study of protein structure, function, and dynamics by NMR spectroscopy.
蛋白质的结构和功能取决于无数的非共价相互作用。直接检测和表征这些弱相互作用在生物大分子，如蛋白质，在实验上是具有挑战性的。在此，我们报告了在蛋白质中首次观察和测量甲基和骨架羰基之间的远程“穿越空间”标量偶合。这些 J 偶合表明存在涉及酰胺π网络的非共价 C-H···π氢键类似相互作用。实验检测到的标量偶合得到自然键轨道分析的证实，该分析揭示了相互作用的轨道性质和穿越空间 J 偶合的起源。通过 NMR 光谱学实验观察到这种 CH···π 相互作用为研究蛋白质结构、功能和动力学增添了新的维度。
