Crystal structure of ethylbenzene dehydrogenase from Aromatoleum aromaticum
Crystal structure of ethylbenzene dehydrogenase from Aromatoleum aromaticum
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DOI：
10.1016/j.str.2006.07.001
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发表时间：
2006-09-01
期刊：
影响因子：
5.7
通讯作者：
Schulz, Georg E.
中科院分区：
文献类型：
--
作者：
Kloer, Daniel P.;Hagel, Corina;Schulz, Georg E.
碳氢化合物的厌氧降解在十年前就被发现了，乙苯脱氢酶是最早被表征的酶之一。在1.88埃分辨率下建立了可溶性165 kDa酶的结构。它是异三聚体。亚基包含催化中心的钼，该中心由两个钼鸟嘌呤二核苷酸组成，其中一个具有开放的吡喃环，以及一个具有组氨酸配体的铁硫簇。在催化过程中，由底物氧化产生的电子被转移到伽马亚基中的血红素，然后可能转移到参与硝酸盐呼吸的单独的细胞色素。β亚基包含四个铁硫簇，在结构上与铁氧还蛋白相关。γ亚基是已知的第一个以蛋氨酸和赖氨酸作为轴向血红素配体的蛋白质。催化产物被模拟成活性中心，显示了反应的几何形状。提出了与乙苯相关化合物的活性和抑制数据一致的机制。
Anaerobic degradation of hydrocarbons was discovered a decade ago, and ethylbenzene dehydrogenase was one of the first characterized enzymes involved. The structure of the soluble periplasmic 165 kDa enzyme was established at 1.88 angstrom resolution. It is a heterotrimer. The alpha subunit contains the catalytic center with a molybdenum held by two molybdopterin-guanine dinucleotides, one with an open pyran ring, and an iron-sulfur cluster with a histidine ligand. During catalysis, electrons produced by substrate oxidation are transferred to a heme in the gamma subunit and then presumably to a separate cytochrome involved in nitrate respiration. The beta subunit contains four iron-sulfur clusters and is structurally related to ferredoxins. The gamma subunit is the first known protein with a methionine and a lysine as axial heme ligands. The catalytic product was modeled into the active center, showing the reaction geometry. A mechanism consistent with activity and inhibition data of ethyl benzene-related compounds is proposed.