Jalilehvand Farideh, Lim Booyong S, Holm R H, Hedman Britt, Hodgson Keith O
Stanford Synchrotron Radiation Laboratory, SLAC, Stanford University, Stanford, California 94309, USA.
Inorg Chem. 2003 Sep 8;42(18):5531-6. doi: 10.1021/ic030039f.
X-ray absorption spectroscopy (XAS) (edge and extended X-ray absorption fine structure (EXAFS)) has been applied to the characterization of three molybdenum(V,VI) monodithiolene complexes with unidentate coligands, MoO(SC(6)H(2)-2,4,6-Pr(i)()(3))(2)(bdt) (1), MoOCl(SC(6)H(2)-2,4,6-Pr(i)(3))(bdt) (2), and MoO(2)(SC(6)H(2)-2,4,6-Pr(i)(3))(bdt) (3) (bdt = benzene-1,2-dithiolate). These complexes are related to the active site in the xanthine oxidase and sulfite oxidase families and, as in the enzyme sites, bind monodentate thiolate. By comparison to the data of crystalline oxidized chicken sulfite oxidase, it is shown that complex 3, whose thiolate simulates binding by the highly conserved cysteine, is an accurate structural analogue of the oxidized site of this enzyme. Normalized edge spectra, EXAFS data, Fourier transforms, and GNXAS-based fit results are presented. As in earlier studies, this provides characterization of new analogue complexes by XAS to facilitate identification of related sites in proteins.
X射线吸收光谱法（XAS）（边吸收和扩展X射线吸收精细结构（EXAFS））已被用于表征三种带有单齿共配体的钼（V,VI）单二硫纶配合物，即MoO(SC(6)H(2)-2,4,6-Pr(i)()(3))(2)(bdt) （1）、MoOCl(SC(6)H(2)-2,4,6-Pr(i)(3))(bdt) （2）和MoO(2)(SC(6)H(2)-2,4,6-Pr(i)(3))(bdt) （3）（bdt = 苯-1,2-二硫醇盐）。这些配合物与黄嘌呤氧化酶和亚硫酸盐氧化酶家族中的活性位点相关，并且如同在酶位点中一样，结合单齿硫醇盐。通过与结晶态氧化鸡亚硫酸盐氧化酶的数据进行比较，结果表明，配合物3的硫醇盐模拟了高度保守的半胱氨酸的结合，是该酶氧化位点的精确结构类似物。文中给出了归一化边谱、EXAFS数据、傅里叶变换以及基于GNXAS的拟合结果。如同早期研究一样，这通过XAS提供了新类似配合物的表征，以促进蛋白质中相关位点的识别。
