OPEN CONFORMATION OF A SUBSTRATE-BINDING CLEFT - F-19 NMR-STUDIES OF CLEFT ANGLE IN THE D-GALACTOSE CHEMOSENSORY RECEPTOR
OPEN CONFORMATION OF A SUBSTRATE-BINDING CLEFT - F-19 NMR-STUDIES OF CLEFT ANGLE IN THE D-GALACTOSE CHEMOSENSORY RECEPTOR
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DOI：
10.1021/bi00240a019
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发表时间：
1991-07-02
期刊：
影响因子：
2.9
通讯作者：
FALKE, JJ
中科院分区：
文献类型：
--
作者：
LUCK, LA;FALKE, JJ
大肠杆菌d -半乳糖和d -葡萄糖受体是一个双结构域结构，在结构域之间的界面上有一个糖结合位点。含有结合d -葡萄糖的闭合裂缝的结构已被晶体学确定，但开放裂缝仍有待表征。本研究说明了一种可推广的方法，用于检测和分析溶液中的开和闭间隙构象。位于裂缝内的F-19核是由F-19核磁共振监测的。当间隙被d -葡萄糖占据时，发现F-19核对顺磁探针Gd是不可接近的。EDTA，验证被占用的裂缝在溶液中是封闭的，并且无法进入散装溶剂。当间隙为空时，顺磁体可以接近F-19核，使得最接近的距离小于等于10埃，这表明空间隙至少以大于等于18±3度的角度暂时打开。
The Escherichia coli D-galactose and D-glucose receptor is a two-domain structure with a sugar-binding site at the interface between domains. The structure of the closed cleft containing bound D-glucose has been determined crystallographically, but the open cleft remains to be characterized. The present study illustrates a generalizable approach that is used to detect and analyze both the open- and closed-cleft conformations in solution. A F-19 nucleus located inside the cleft is monitored by F-19 NMR. When the cleft is occupied by D-glucose, the F-19 nucleus is found to be inaccessible to the aqueous paramagnetic probe Gd.EDTA, verifying that the occupied cleft is closed in solution and inaccessible to bulk solvent. When the cleft is empty, the F-19 nucleus becomes accessible to the paramagnet such that the distance of closest approach is r less-than-or-equal-to 10 angstrom, indicating that the empty cleft opens at least transiently by an angle-theta greater-than-or-equal-to 18 +/- 3-degrees.