Structure of a xanthine oxidase-related 4-hydroxybenzoyl-CoA reductase with an additional [4Fe-4S] cluster and an inverted electron flow.
Structure of a xanthine oxidase-related 4-hydroxybenzoyl-CoA reductase with an additional [4Fe-4S] cluster and an inverted electron flow.
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DOI：
10.1016/j.str.2004.10.008
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发表时间：
2004-12
期刊：
影响因子：
5.7
通讯作者：
M. Unciuleac;E. Warkentin;C. C. Page-C.;M. Boll;U. Ermler
中科院分区：
文献类型：
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作者：
M. Unciuleac;E. Warkentin;C. C. Page-C.;M. Boll;U. Ermler
Mo-flavo-Fe/S-dependent heterohexameric protein complex 4-hydroxybenzoyl-CoA reductase （4-HBCR, dehydroxylating）是酚类化合物厌氧降解的中心酶，属于黄嘌呤氧化酶（XO）家族。在1.6 Å分辨率下建立了其x射线结构。4-HBCR与XO家族的其他结构特征成员之间最显著的区别是在β亚基中插入了40个氨基酸，该亚基在FAD的异alloxazine环的16.5 Å处携带了一个额外的[4Fe-4S]簇。4-HBCR的结构和随之进行的电子转移速率计算表明，从给体铁氧还蛋白通过[4Fe-4S]簇到Mo的反向电子转移链距离为55 Å。4-羟基苯甲酰辅酶a的结合位点位于一条18 Å长的通道中，该通道由芳香部分周围的几个芳香侧链排列，这些侧链被认为是在催化过程中屏蔽和稳定假设的自由基中间体。
The Mo-flavo-Fe/S-dependent heterohexameric protein complex 4-hydroxybenzoyl-CoA reductase (4-HBCR, dehydroxylating) is a central enzyme of the anaerobic degradation of phenolic compounds and belongs to the xanthine oxidase (XO) family of molybdenum enzymes. Its X-ray structure was established at 1.6 Å resolution. The most pronounced difference between 4-HBCR and other structurally characterized members of the XO family is the insertion of 40 amino acids within the β subunit, which carries an additional [4Fe-4S] cluster at a distance of 16.5 Å to the isoalloxazine ring of FAD. The architecture of 4-HBCR and concomitantly performed electron transfer rate calculations suggest an inverted electron transfer chain from the donor ferredoxin via the [4Fe-4S] cluster to the Mo over a distance of 55 Å. The binding site of 4-hydroxybenzoyl-CoA is located in an 18 Å long channel lined up by several aromatic side chains around the aromatic moiety, which are proposed to shield and stabilize the postulated radical intermediates during catalysis.