HIGH-RESOLUTION SOLUTION STRUCTURES OF OXIDIZED AND REDUCED ESCHERICHIA-COLI THIOREDOXIN
HIGH-RESOLUTION SOLUTION STRUCTURES OF OXIDIZED AND REDUCED ESCHERICHIA-COLI THIOREDOXIN
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DOI：
10.1016/s0969-2126(94)00086-7
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发表时间：
1994-09-15
期刊：
影响因子：
5.7
通讯作者：
DYSON, HJ
中科院分区：
文献类型：
--
作者：
JENG, MF;CAMPBELL, AP;DYSON, HJ
背景资料：硫氧还蛋白参与巯基-二硫键交换反应，并且在生理条件下发现氧化硫氧还蛋白（二硫键形式）和还原硫氧还蛋白（二巯基形式）。以前的结构研究表明，mio的形式是非常相似的，虽然存在显着的功能和光谱差异。因此，魏氏进行了高分辨率的解决方案的结构研究的两种形式的大肠杆菌硫氧还蛋白，以检测微妙的构象differentiations.Results：还原和氧化的硫氧还蛋白的解决方案的结构是非常相似的。两种形式的骨架结构基本相同，活性位点区域略有差异，包括Cys 32和Cys 35。Cys 32的侧链硫原子在蛋白质的还原形式中远离Cys 35的侧链硫原子倾斜，以适应二硫化物还原时发生的S-S距离的增加，但两个半胱氨酸的（chi）1角在两种离子中保持相同。在改变活性位点半胱氨酸的氧化态时仅发生细微的构象变化，包括一些侧链的位置和活性部位区域中的氢键模式。因此，这两种形式之间的功能差异可能与活性位点环内和附近的局部构象灵活性差异有关。
Background: Thioredoxin participates in thiol-disulfide exchange reactions and both oxidized thioredoxin (disulfide form) and reduced thioredoxin (dithiol form) are found under physiological conditions. Previous structural studies suggested that the mio forms were extremely similar, although significant functional and spectroscopic differences exist. Wie therefore undertook high-resolution solution structural studies of the two forms of Escherichia coli thioredoxin in order to detect subtle conformational differences.Results: The solution structures of reduced and oxidized thioredoxin are extremely similar. Backbone structure is largely identical in the two forms, with slight differences in the region of the active site, which includes Cys32 and Cys35. The side chain sulfur atom of Cys32 is tilted away from that of Cys35 in the reduced form of the protein to accommodate the increase in S-S distance that occurs upon reduction of the disulfide, but the (chi)1 angles of the two cysteines remain the same in the two ions.Conclusions: Only subtle conformational changes occur upon changing the oxidation state of the active site cysteines, including the positions of some side chains and in hydrogen bonding patterns in the active site region. Functional differences between the two forms are probably therefore related to differences in local conformational flexibility in and near the active site loop.