X-Ray Resonance Raman Spectroscopy of Mn and Ni Metalloproteins

该奖项由无机、生物无机和有机金属化学项目颁发，支持加州大学戴维斯分校化学系Stephen P. Cramer教授和应用科学系助理研究科学家Uwe Bergmann的研究，以开发x射线共振拉曼光谱（XRRS）作为探测低能激发的工具。低能跃迁将涉及电荷转移和d-d波段以及蛋白质系统中涉及金属离子的分子振动。在含镍酶中，无论是Fe还是Ni，金属3d到配体（CO） pi*的跃迁都被Fe- s簇中硫到铁的激发所掩盖。在光系统ii中，Mn - d-d波段只能在叶绿素截止线以上和水下近红外波段以下的狭窄光谱窗口内看到。XRRS应用于蛋白质系统的发展将使观察被其他发色团掩盖的金属中心转变成为可能，这将有助于表征铁-镍脱氢酶、一氧化碳脱氢酶、光系统ii和其他重要的锰和镍酶的一些鲜为人知但重要的中间体，这些中间体对理解基本的生物过程至关重要。将开发一种新的x射线光谱技术来探测重要蛋白质中心的活性位点。

This award by the Inorganic, Bioinorganic and Organometallic Chemistry program supports research by Professor Stephen P. Cramer in the Department of Chemistry and Uwe Bergmann, Assistant Research Scientist in the Department of Applied Sciences, at the University of California at Davis to develop x-ray resonance Raman spectroscopy (XRRS) as a tool to probe low-energy excitations. The low energy transitions will involve charge transfer and d-d bands as well as molecular vibrations involving metal ions in protein systems. In nickel enzymes, with either Fe or Ni, metal 3d to ligand (CO) pi* transitions are obscured by sulfur to iron excitations in Fe-S clusters. In photosystem-II, Mn d-d bands can only be seen over a narrow spectroscopic window above the chlorophyl cutoff and below water near infrared bands. The development of XRRS as applied to protein systems will enable the observation of metal-centered transitions that are obscured by other chromophores, which could help to characterize some of the poorly understood, but important, intermediates in Fe-Ni dehydrogenase, carbon monoxide dehydrogenase, photosystem-II and other important Mn and Ni enzymes that are essential to understanding fundamental biological processes.A new x-ray spectroscopic technique will be developed to probe active sites in important protein centers.