STAFF PRIORITY TIME XAS OF DESULFOVIBRIO DESULFURICANS FORMATE DEHYDROGENASE

我们研究了氧化态和氧化态的活性中心结构。 脱硫弧菌的二亚硫酸盐还原甲酸脱氢酶 在Mo和Se K边都使用XAS的脱硫剂。从 钼透视下的氧化钼(VI)活性中心有四个钼-S 配体(配位双二联二硫戊烯辅因子)， 一个Mo=O和一个Mo-Se，而还原的Mo(IV)活性中心 含四个钼-S，一个钼-氧(-OH或-OH2)和一个钼-硒。来自Se的 从角度来看，氧化的蛋白质除了Se-Mo和 预期的Se-C配体，一个键长为2.19E的Se-S被还原。 蛋白质这一硒-S并不存在。这种协调类似于 观察到的大肠杆菌甲酸脱氢酶(G.N.George，C.M. 首页--期刊主要分类--期刊细介绍--期刊题录与文摘--期刊详细文摘内容 C·斯塔特曼·J·阿梅尔化学。SoC。1998年，接受出版)， 但在脱硫菌中，二亚硫酸盐酶可降低 SE-S债券。

We have studied the active site structure of oxidized and dithionite-reduced formate dehydrogenase from Desulfovibrio desulfuricans using XAS at both the Mo and Se K-edges. From the molybdenum perspective the oxidized Mo(VI) active site has four Mo-S ligands (consitant with a bis-pterindithiolene cofactor coordination), with one Mo=O and one Mo-Se, while the reduced Mo(IV) active site contains four Mo-S, one Mo-O (-OH or -OH2) and one Mo-Se. From the Se perspective, the oxidized protein has, in addition to the Se-Mo and Se-C ligands expected, a Se-S with a bond-length of 2.19 E. In reduced protein this Se-S is not present. This coordination is similar to that observed for E. coli formate dehydrogenase (G. N. George, C. M. Colangelo, J. Dong, R. A. Scott, S. V. Khangulov, V. N. Gladyshev, T. C. Stadtman J. Amer. Chem. Soc. 1998, accepted for publication), except that in the D. desulfuricans enzyme dithionite can reduce the Se-S bond.