3-DIMENSIONAL SOLUTION STRUCTURE OF THE REDUCED FORM OF ESCHERICHIA-COLI THIOREDOXIN DETERMINED BY NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY
3-DIMENSIONAL SOLUTION STRUCTURE OF THE REDUCED FORM OF ESCHERICHIA-COLI THIOREDOXIN DETERMINED BY NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY
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DOI：
10.1021/bi00469a016
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发表时间：
1990-05-01
期刊：
影响因子：
2.9
通讯作者：
WRIGHT, PE
中科院分区：
文献类型：
--
作者：
DYSON, HJ;GIPPERT, GP;WRIGHT, PE
利用1H NMR获得的距离约束和二面角约束，确定了大肠杆菌中还原（二硫醇）硫氧还蛋白的三维溶液结构。还原硫氧还蛋白具有明确的全局折叠，由中心五股组成。——床单和三个长螺旋。度量。-线按.beta.1.beta.3.beta.2.beta.4.beta的顺序装入片中。5、带。beta。1,度量。3和。beta。2平行和。2,度量。4和。以反平行的方式排列的其中两个螺旋连接着。β的链。表:.alpha。1在。之间。1和。2和。2之间。2 .和。股度量。4和。beta。5个由一个短环路连接，其中包含一个。β。-凸起。股度量。3和。其中4个由一个长环连接，这个长环包含了一系列类似旋转或310个螺旋的结构。活性位点Cys-Gly-Pro-Cys序列在β链之间形成一个突出的环。2和螺旋。alpha。2。总体结构与x射线晶体结构分析得到的氧化（二硫）硫氧还蛋白非常相似，但活性位点环的局部构象不同。cys32和cys35的硫距从2.05 . ang开始增大。在二硫桥到6.8 .+-。0.6 .ANG。在还原硫氧还蛋白的二硫醇中，由于cys35侧链的旋转和Pro 34位置的显著变化。这种构象变化对硫氧还蛋白作为蛋白质二硫氧化还原酶的作用机制具有重要意义。
The three-dimensional solution structure of reduced (dithiol) thioredoxin from Escherichia coli has been determined with distance and dihedral angle constraints obtained from 1H NMR spectroscopy. Reduced thioredoxin has a well-defined global fold consisting of a central five-strand .beta.-sheet and three long helices. The .beta.-strands are packed in the sheet in the order .beta.1.beta.3.beta.2.beta.4.beta.5, with .beta.1, .beta.3, and .beta.2 parallel and .beta.2, .beta.4, and .beta.5 arranged in an antiparallel fashion. Two of the helices connect strands of the .beta.-sheet: .alpha.1 between .beta.1 and .beta.2 and .alpha.2 between .beta.2 and .beta.3. Strands .beta.4 and .beta.5 are connected by a short loop that contains a .beta.-bulge. Strands .beta.3 and .beta.4 are connected by a long loop that contains a series of turn-like or 310 helical structures. The active site Cys-Gly-Pro-Cys sequence forms a protruding loop between strand .beta.2 and helix .alpha.2. The structure is very similar overall to that of oxidized (disulfide) thioredoxin obtained from X-ray crystal structure analysis but differs in the local conformation of the active site loop. The distance between the sulfurs of Cys 32 and Cys 35 increases from 2.05 .ANG. in the disulfide bridge to 6.8 .+-. 0.6 .ANG. in the dithiol of reduced thioredoxin, as a result of a rotation of the side chain of Cys 35 and a significant change in the position of Pro 34. This conformational change has important implications for the mechanism of thioredoxin as a protein disulfide oxidoreductase.