1H NMR titration experiments have been used to establish that minimal proline-based models show enhanced binding selectivity towards phenol in CDCl3, relative to other similarly protected amino acid residues. Cooperative binding effects appear to play a role, with sarcosine models affording binding constants to phenol intermediate to those obtained from proline models and other amino acid models. The mechanism for binding, based on DFT calculations and the application of Hunter's molecular recognition toolbox model, cannot be solely attributed to hydrogen bond strength, and appears to be mediated through CâH-Ï bonds and the rotational freedom of the amide substrate.
1H NMR 滴定实验证明,相对于其他类似的受保护
氨基酸残基,基于脯
氨酸的最小模型在 CDCl3 中对
苯酚的结合选择性更强。协同结合效应似乎在其中发挥了作用,
肌氨酸模型与
苯酚的结合常数介于脯
氨酸模型和其他
氨基酸模型得到的结合常数之间。根据 DFT 计算和亨特分子识别工具箱模型的应用,结合机制不能完全归因于氢键强度,而似乎是通过 CâH-Ï 键和酰胺底物的旋转自由度介导的。