融合吡啶受体裂隙中糖识别的圆二色性读数
Circular dichroism readout of sugar recognition in the cleft of a fused-pyridine receptor.
作者信息
Tamaru Shun-ichi, Shinkai Seiji, Khasanov Alisher B, Bell Thomas W
机构信息
Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Fukuoka 812-8581, Japan.
出版信息
Proc Natl Acad Sci U S A. 2002 Apr 16;99(8):4972-6. doi: 10.1073/pnas.082638599.
Dicarboxamide host 2 forms 1:1 complexes with n-octyl pyranosides derived from D-glucose, D-mannose, D-galactose, D-fucose, D-lyxose, and D-arabinose. Association constants (K(a)) in the range of 77-940 M(-1) were measured in chloroform by means of induced circular dichroism and fluorescence spectroscopy. Variations in K(a) values correspond qualitatively to expected differences in hydrogen-bonding abilities of guest hydroxyl groups. Induced circular dichroism effects for complexes of saccharides bearing equatorial 3-OH, 4-OH, and 6-OH groups show that the host chromophore is twisted in a P-helical conformation. A structural model is proposed that is also consistent with the results of previous studies involving complexation of dicarboxylic acid 1 with cationic saccharides in methanol.
二羧酰胺主体2与源自D - 葡萄糖、D - 甘露糖、D - 半乳糖、D - 岩藻糖、D - 来苏糖和D - 阿拉伯糖的正辛基吡喃糖苷形成1:1配合物。通过诱导圆二色性和荧光光谱法在氯仿中测量了缔合常数（K(a)），其范围为77 - 940 M(-1)。K(a)值的变化在质量上与客体羟基氢键能力的预期差异相对应。对于带有赤道面3 - OH、4 - OH和6 - OH基团的糖类配合物的诱导圆二色性效应表明，主体发色团以P - 螺旋构象扭曲。提出了一个结构模型，该模型也与先前关于二羧酸1与甲醇中的阳离子糖类络合的研究结果一致。
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