Giachini Lisa, Francia Francesco, Boscherini Federico, Pacelli Consiglia, Cocco Tiziana, Papa Sergio, Venturoli Giovanni
Department of Biology, University of Bologna, Via Irnerio n 42, 40126, Bologna, Italy.
FEBS Lett. 2007 Dec 11;581(29):5645-8. doi: 10.1016/j.febslet.2007.11.019. Epub 2007 Nov 20.
The metal content of bovine NADH-Q oxidoreductase determined by inductively-coupled plasma atomic-emission spectroscopy reveals the presence of about one atom of zinc per molecule of flavin mononucleotide. We applied Zn K-edge extended X-ray absorption fine structure spectroscopy (EXAFS) to investigate the local structure of the bound zinc ion and to identify the nature of the coordinating residues. The EXAFS spectrum is consistent with a structured zinc binding site. By combining information from first-shell analysis and from metalloprotein data bases putative binding clusters have been built and fitted to the experimental spectrum using ab initio simulations. The best fitting binding cluster is formed by two histidine and two cysteine residues arranged in a tetrahedral geometry.
通过电感耦合等离子体原子发射光谱法测定的牛NADH-Q氧化还原酶的金属含量表明，每分子黄素单核苷酸中存在约一个锌原子。我们应用锌K边扩展X射线吸收精细结构光谱法（EXAFS）来研究结合锌离子的局部结构，并确定配位残基的性质。EXAFS光谱与结构化的锌结合位点一致。通过结合来自第一壳层分析和金属蛋白数据库的信息，构建了推定的结合簇，并使用从头算模拟将其拟合到实验光谱中。最佳拟合的结合簇由两个组氨酸和两个半胱氨酸残基以四面体几何结构排列形成。
