Atomic basis of the exquisite specificity of phosphate and sulfate transport receptors.
Atomic basis of the exquisite specificity of phosphate and sulfate transport receptors.
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磷酸盐和硫酸盐转运受体精细特异性的原子基础。
DOI：
10.1038/ki.1996.132
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发表时间：
1996
影响因子：
19.6
通讯作者：
F. Quiocho
中科院分区：
文献类型：
--
作者：
F. Quiocho
我们已经确定，通过X射线晶体学的方法，1.7 A分辨率的三维结构的配体结合形式的磷酸盐受体以及硫酸盐受体。这些蛋白质结构提供了一个前所未有的原子水平的理解机制，控制每个受体的精致特异性。虽然它们缺乏氨基酸序列同源性，但两种受体具有非常相似的三维结构。该结构由两个球状结构域组成，它们被包含配体结合位点的深裂分开。结合的磷酸盐和硫酸盐完全没有水合水。结合的磷酸盐通过12个氢键紧密地保持在适当的位置，11个与供体基团结合，1个与受体基团结合。受体基团（Asp羧酸酯侧链）起着三个关键作用。它通过直接识别磷酸一丁酯或磷酸氢二酯的一个质子来赋予特异性。它还有助于识别磷酸一丁酯的另一个质子。最后，由于电荷排斥，它不允许完全电离的硫酸盐结合。与硫酸盐受体结合的硫酸盐仅与不带电的极性基团形成七个氢键。硫酸盐受体结合位点缺乏受体基团不利于磷酸盐结合。
We have determined, by the method of x-ray crystallography, the 1.7 A resolution three-dimensional structures of the ligand-bound form of the phosphate receptor as well as the sulfate receptor. These protein structures provide an unprecedented atomic-level understanding of the mechanism governing the exquisite specificity of each receptor. Although they lack amino acid sequence homology, both receptors have very similar three-dimensional structure. The structure consists of two globular domains separated by a deep cleft which contains the ligand-binding site. The bound phosphate and sulfate are totally devoid of water of hydration. The bound phosphate is tightly held in place by 12 hydrogen bonds, 11 with donor and 1 with acceptor groups. The acceptor group (an Asp carboxylate side chain) plays three key roles. It confers specificity by directly recognizing one proton of either the monobasic or dibasic phosphate. It also assists in the recognition of another proton of the monobasic phosphate. Finally, because of charge repulsion, it disallows binding of fully ionized sulfate. The sulfate bound to the sulfate receptor makes seven hydrogen bonds with uncharged polar groups exclusively. The absence of an acceptor group in the binding site of the sulfate receptor is not conducive to phosphate binding.
图 2 参与鼠伤寒沙门氏菌主动转运的硫酸盐结合蛋白的解析结构。
影响因子：
5.6
作者：
Pflugrath,JW;Quiocho,FA
通讯作者：
Quiocho,FA
DOI：
10.1073/pnas.88.5.2026
发表时间：
1991-03-01
影响因子：
11.1
作者：
AQVIST, J;LUECKE, H;WARSHEL, A
通讯作者：
WARSHEL, A