Structural and Functional Insights into Sulfide:Quinone Oxidoreductase
Structural and Functional Insights into Sulfide:Quinone Oxidoreductase
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DOI：
10.1021/bi9003827
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发表时间：
2009-06-23
期刊：
影响因子：
2.9
通讯作者：
Archer, Margarida
中科院分区：
文献类型：
--
作者：
Brito, Jose A.;Sousa, Filipa L.;Archer, Margarida
硫化物：醌氧化还原酶（SQR）是从超嗜热嗜酸古菌Acidianus ambivalens的膜中分离出来的，它的X射线结构，首次报道的SQR，被确定为2.6埃分辨率。该酶的功能和结构特征，并显示有两个氧化还原活性位点：共价结合的FAD和相邻的半胱氨酸残基对。最有趣的是，X射线结构揭示了存在一个三个硫原子的链桥接这两个半胱氨酸残基。讨论了这一发现在硫化物氧化催化机制中的可能意义，并讨论了SQR在硫依赖的A. ambivalens，链接到氧还原，是解决。
A sulfide:quinone oxidoreductase (SQR) was isolated from the membranes of the hyperthermoacidophilic archaeon Acidianus ambivalens, and its X-ray structure, the first reported for an SQR, was determined to 2.6 angstrom resolution. This enzyme was functionally and structurally characterized and was shown to have two redox active sites: a covalently bound FAD and an adjacent pair of cysteine residues. Most interestingly, the X-ray structure revealed the presence of a chain of three sulfur atoms bridging those two cysteine residues. The possible implications of this observation in the catalytic mechanism for sulfide oxidation are discussed, and the role of SQR in the sulfur dependent bioenergetics of A. ambivalens, linked to oxygen reduction, is addressed.