Structural basis for multiple ligand specificity of the periplasmic lysine-, arginine-, ornithine-binding protein.
Structural basis for multiple ligand specificity of the periplasmic lysine-, arginine-, ornithine-binding protein.
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DOI：
10.2210/pdb1laf/pdb
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发表时间：
1995-07
期刊：
影响因子：
--
通讯作者：
Byung-Ha Oh;G. Ames;Sung-HouK Kim
中科院分区：
文献类型：
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作者：
Byung-Ha Oh;G. Ames;Sung-HouK Kim
具有多重特异性的蛋白质的底物结合位点应满足几种不同底物的几何和能量互补性。通过测定和分析未配体和与三种高亲和力配体（L-赖氨酸、L-精氨酸和L-鸟氨酸）和一种低亲和力配体（L-组氨酸）配体配体的蛋白质的结构，研究了周质赖氨酸、精氨酸和鸟氨酸结合蛋白（LAO）的多配体特异性的结构基础。几何互补性主要通过配体结合位点的大尺寸实现，所述配体结合位点可以容纳四个配体加上三个水分子的最大共同体积。能量互补性的优化是通过蛋白质结合水分子的重新定位和Asp-11侧链的移动来实现的。LAO-组氨酸复合物的结构表明，蛋白质对组氨酸的亲和力降低30倍主要是由于组氨酸侧链与蛋白质的一种离子相互作用不可用，该离子相互作用存在于其他三种复合物中。
The substrate-binding site of a protein with multiple specificity should satisfy geometric and energetic complementarity for several different substrates. The structural basis of the multiple ligand specificity of the periplasmic lysine-, arginine-, ornithine-binding protein (LAO) was investigated by determining and analyzing the structures of the protein unliganded and liganded with each of the three high-affinity ligands (L-lysine, L-arginine, and L-ornithine) and with one low-affinity ligand (L-histidine). The geometric complementarity is achieved primarily by virtue of the large size of the ligand-binding site which can accommodate the maximum common volume of the four ligands plus three water molecules. The optimization of energetic complementarity is achieved by the relocation of protein-bound water molecules and by the movement of the Asp-11 side chain. The structure of the LAO-histidine complex indicates that the 30-fold reduced affinity of the protein for histidine is primarily due to unavailability of one ionic interaction of the histidine side chain with the protein which is present in the other three complexes.