Orientation of the g-tensor axes of the Rieske subunit in the cytochrome bc1 complex
Orientation of the g-tensor axes of the Rieske subunit in the cytochrome bc1 complex
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DOI：
10.1021/bi034620z
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发表时间：
2004-01-20
期刊：
影响因子：
2.9
通讯作者：
Kramer, DM
中科院分区：
文献类型：
--
作者：
Bowman, MK;Berry, EA;Kramer, DM
Rieske铁硫蛋白亚基g-张量的取向在牛线粒体细胞色素bc（1）复合物的Q（0）醌结合位点与stigmatellin的单晶中确定。g张量主轴相对于2Fe 2S团簇中的Fe-Fe和S-S原子方向是偏斜的，这是由于团簇缺乏严格对称性所允许的。晶体中的不对称单元是活性二聚体，g张量轴相对于二聚体两半中的铁硫簇具有略微不同的取向。与1.79轴相似的g相对于Fe-Fe方向的平均角度为30度，与2.024轴相似的g相对于S-S方向的平均角度为26度。g-张量轴方向的这种分配表明，细胞色素bc（1）和B（6 f）复合物中的Rieske蛋白的构象可能是相同的，并且Rieske头部结构域在催化循环期间的运动程度在这些远亲复合物的进化过程中是高度保守的。
The orientation of the g-tensors of the Rieske iron-sulfur protein subunit was determined in a single crystal of the bovine mitochondrial cytochrome bc(1) complex with stigmatellin in the Q(0) quinol binding site. The g-tensor principal axes are skewed with respect to the Fe-Fe and S-S atom direction in the 2Fe2S cluster, which is allowed by the lack of rigorous symmetry of the cluster. The asymmetric unit in the crystal is the active dimer, and the g-tensor axes have slightly different orientations relative to the iron-sulfur cluster in the two halves of the dimer. The g similar to 1.79 axis makes an average angle of 30degrees with respect to the Fe-Fe direction and the g similar to 2.024 axis an average angle of 26degrees with respect to the S-S direction. This assignment of the g-tensor axis directions indicates that conformations of the Rieske protein are likely the same in the cytochrome bc(1) and b(6f) complexes and that the extent of motion of the Rieske head domain during the catalytic cycle has been highly conserved during evolution of these distantly related complexes.