Ishida T, Ueda H, Segawa K, Doi M, Inoue M
Department of Physical Chemistry, Osaka University of Pharmaceutical Sciences, Japan.
Arch Biochem Biophys. 1990 Apr;278(1):217-27. doi: 10.1016/0003-9861(90)90251-s.
In order to investigate the mode of interaction between the N-quarternized cytosine base and the aromatic amino acid, the crystal structure of the 3-methyl-cytidine-5'-monophosphate:tryptamine complex was analyzed by X-ray diffraction. The complex crystals were stabilized by extensive hydrogen bond formations in which eight independent water molecules per complex pair participated. A prominent stacking interaction, characterized by a parallel alignment of both rings with a separation distance of ca. 3.4 A, was observed between the cytosine base and the indole ring. Combining the present results with X-ray crystallographic data on the adenine--and guanine--aromatic amino acid interactions, we summarize the structural characteristics observed in the stacking interaction of the N-quarternized nucleic acid base with the aromatic amino acid and discuss their biological implications, especially in connection with the significance of N-protonation of nucleic acid base for selective recognition by protein.
为了研究N-季铵化胞嘧啶碱基与芳香族氨基酸之间的相互作用模式，通过X射线衍射分析了3-甲基胞苷-5'-单磷酸：色胺复合物的晶体结构。复合物晶体通过广泛的氢键形成得以稳定，每个复合物对中有八个独立的水分子参与其中。在胞嘧啶碱基和吲哚环之间观察到一种显著的堆积相互作用，其特征是两个环平行排列，间距约为3.4埃。将目前的结果与关于腺嘌呤和鸟嘌呤与芳香族氨基酸相互作用的X射线晶体学数据相结合，我们总结了在N-季铵化核酸碱基与芳香族氨基酸的堆积相互作用中观察到的结构特征，并讨论了它们的生物学意义，特别是与核酸碱基的N-质子化对蛋白质选择性识别的重要性相关的意义。
