个人简介

Education: B.S., 1969, University of Virginia; Ph.D., 1972, University of California at Berkeley Awards: NATO Postdoctoral Fellow, E.T.H. (Zurich) 1972-73, Alfred P. Sloan Foundation Fellow, 1976-78; Sidhu Award for Contributions to X-ray Diffraction, 1978; World Bank Lecturer, 1984, E.O. Lawrence Award, 2002

研究领域

Bioinorganic/Biophysical/Inorganic/Structural

Our research involves the fields of bioinorganic and biophysical chemistry. In general, we are asking how structure at different organizational levels relates to function. Studies are being done at the molecular and macromolecular levels using a number of x-ray spectroscopic and scattering techniques on a variety of different scientific problems. Typical of our molecular structural studies are investigations of metal ions as active sites of biomolecules. We are developing and utilizing techniques such as x-ray absorption spectroscopy (XAS) to study the electronic and metrical details of a given metal ion in solution.1,2,4 XAS uses a brilliant source of electromagnetic radiation called synchrotron radiation which is available nearby at the Stanford Synchrotron Radiation Laboratory (SSRL), where we have an extensive research program. One area of particular interest is the active site of the enzyme nitrogenase, responsible for conversion of atmospheric dinitrogen to ammonia. Our XAS studies have revealed that the molybdenum is contained in a polynuclear Mo-Fe-S cluster. From XAS studies at S, Fe and Mo, we have studied the electronic distribution as a function of redox in this cluster. We have recently developed new methods to study long distances in the cluster within and outside the protein. Studies are now ongoing to learn how this cluster functions during catalysis and interacts with substrates and inhibitors. Other components of the protein are also under active study. Other projects include the study of iron in dioxygen activation and oxidation (in the binuclear iron-containing enzyme methane monooxygenase and in cytochrome oxidase). We are also investigating the role of copper in electron transport and in dioxygen activation. Other studies include the electronic structure2 of iron-sulfur clusters in models and enzymes. On a macromolecular level, we are interested in solution structure and protein folding. This necessitates studying the conformation of macromolecules using both static and time-resolved measurements. We are using solution small angle x-ray scattering to study the role of protein conformation in mediating electron transfer in nitrogen fixation, to study protein folding pathways in lysozyme and cytochrome c, and to investigate ATP-induced conformational changes. We are also developing new approaches using x-ray free electron laser radiation to image noncrystalline biomolecules and solve the classic "phase problem" in crystallography.3

近期论文

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"Structural Characterization of Metallopeptides Designed as Scaffolds for the Stabilization of Nickel(II)-Fe4S4 Bridged Assemblies by X-ray Absorption Spectroscopy," K.B. Musgrave, C.E. Laplaza, R.H. Holm, B. Hedman, and K.O. Hodgson, J. Amer. Chem. Soc., 124, 3083-3092 (2002). "Sulfur K-edge X-ray Absorption Spectroscopy of [2Fe-2S] Ferredoxin: Covalency of the Oxidized and Reduced 2Fe Forms and Comparison to Model Complexes," E. Anxolabéhère-Mallart, T. Glaser, P. Frank, A. Aliverti, G. Zanetti, B. Hedman, K.O. Hodgson, and E.I. Solomon, J. Amer. Chem. Soc.,123, 5444-5452 (2001). "A New Approach to 3-D Structures of Biomolecules Utlizing Single Molecule Diffraction Images," J. Miao, K.O. Hodgson, and D. Sayre, Proc. Natl. Acad. Sci. USA, 98, 6641-6645 (2001). "Ligand K-edge X-ray Absorption Spectroscopy: A Direct Probe of Ligand-Metal Covalency," T. Glaser, B. Hedman, K.O. Hodgson, and E.I. Solomon, Acc. Chem. Res., 33, 859-868 (2000).