The bacterial periplasmic histidine-binding protein. structure/function analysis of the ligand-binding site and comparison with related proteins.
The bacterial periplasmic histidine-binding protein. structure/function analysis of the ligand-binding site and comparison with related proteins.
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DOI：
10.2210/pdb1hpb/pdb
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发表时间：
1995-01
期刊：
影响因子：
--
通讯作者：
B. Oh;C. Kang;H. D. Bondt;Sung-Hou Kim;K. Nikaido;A. Joshi;G. Ames
中科院分区：
文献类型：
--
作者：
B. Oh;C. Kang;H. D. Bondt;Sung-Hou Kim;K. Nikaido;A. Joshi;G. Ames
细菌周质结合蛋白是细菌主动跨膜转运和/或趋化过程中的初始受体。其中，组氨酸结合蛋白（HisJ）已经从生化、生理和遗传的角度进行了广泛的研究。与组氨酸复合的组氨酸结合蛋白的三维晶体结构已通过分子置换法以2.5-A分辨率测定，所述分子置换法使用先前解决的赖氨酸、精氨酸、鸟氨酸结合蛋白（LAO）的赖氨酸配体结构，其与HisJ共享70%的序列同一性。结构为双叶型;这两个叶（一个比另一个大）通过两条短链连接，并且彼此接触（闭合）包围组氨酸。带电、极性和非极性侧链以及肽骨架参与组氨酸的紧密结合。结合的组氨酸涉及八个直接氢键，六个与较大的叶和两个与较小的叶，在一个潜在的水介导的氢键与较大的叶，以及在离子相互作用。围绕配体的HisJ残基与与赖氨酸相互作用的LAO残基相同，除了残基52，其在HisJ中是亮氨酸，在LAO中是苯丙氨酸。HisJ中的Leu-52与组氨酸的咪唑环产生疏水相互作用。在影响配体结合位点的7个突变中，5个位于配体结合位点，1个位于连接链，1个位于结构域界面。基于相关结合蛋白之间的比较，预测了谷氨酰胺结合蛋白和意见结合蛋白的配体和各自的结合蛋白残基之间的特异性相互作用。
Bacterial periplasmic binding proteins are initial receptors in the process of active transport across cell membranes and/or chemotaxis. Among them, the histidine-binding protein (HisJ) has been extensively studied from the biochemical, physiological, and genetic points of view. The three-dimensional crystal structure of the histidine-binding protein complexed with histidine has been determined at 2.5-A resolution by the molecular replacement method using a probe structure the previously solved lysine-liganded structure of the lysine-, arginine-, ornithine-binding protein (LAO), which shares 70% sequence identity with HisJ. The structure is bi-lobate; the two lobes, one bigger than the other, are connected by two short strands and are in contact with each other (closed) enclosing the histidine. Charged, polar, and non-polar side chains, as well as the peptide backbone, are involved in tight binding of the histidine. The bound histidine is involved in eight direct hydrogen bonds, six with the bigger lobe and two with the smaller lobe, in one potential water-mediated hydrogen bond with the bigger lobe, as well as in ionic interactions. The HisJ residues surrounding the ligand are the same as the LAO residues interacting with lysine, except for residue 52 which is leucine in HisJ and phenylalanine in LAO. The Leu-52 in HisJ makes a hydrophobic interaction with the imidazole ring of histidine. Of seven mutations affecting the ligand-binding site, five are located in the ligand-binding site, one in a connecting strand, and one at the domains interface. Based on comparisons among related binding proteins, the specific interactions between the ligands and the respective binding protein residues are predicted for the glutamine-binding protein and the opines-binding protein.