A5072260476- Metal-Catalyzed Oxygenation Mechanisms
- Metal complexes synthesis and properties
- Enzyme Structure and Function
- Metalloenzymes and iron-sulfur proteins
- X-ray Spectroscopy and Fluorescence Analysis
- Magnetism in coordination complexes
- Porphyrin and Phthalocyanine Chemistry
- Electrocatalysts for Energy Conversion
- Protein Structure and Dynamics
- Radioactive element chemistry and processing
- Electrochemical Analysis and Applications
- Photosynthetic Processes and Mechanisms
- Porphyrin Metabolism and Disorders
- X-ray Diffraction in Crystallography
- Biochemical and Molecular Research
- Electron and X-Ray Spectroscopy Techniques
- Lanthanide and Transition Metal Complexes
- Advanced X-ray Imaging Techniques
- Trace Elements in Health
- Crystallization and Solubility Studies
- Polyoxometalates: Synthesis and Applications
- Enzyme-mediated dye degradation
- Ammonia Synthesis and Nitrogen Reduction
- RNA and protein synthesis mechanisms
- Vanadium and Halogenation Chemistry
Stanford Synchrotron Radiation Lightsource
2016-2025
Stanford University
2016-2025
SLAC National Accelerator Laboratory
2016-2025
Fermi National Accelerator Laboratory
2015-2023
Stanford Medicine
2018
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati
2005-2016
Joint Center for Structural Genomics
2002-2014
University of California, Irvine
1989-2011
Monash University
2009-2010
University at Buffalo, State University of New York
2008-2010
X-ray absorption Fe−K edge data on ferrous and ferric model complexes have been studied to establish a detailed understanding of the 1s → 3d pre-edge feature its sensitivity electronic structure iron site. The energy position splitting, intensity distribution, were found vary systematically with spin state, oxidation geometry, bridging ligation (for binuclear complexes). A methodology for interpreting splitting distribution features was developed high-spin in octahedral, tetrahedral, square...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTX-ray absorption edge determination of the oxidation state and coordination number copper. Application to type 3 site in Rhus vernicifera laccase its reaction with oxygenLung Shan Kau, Darlene J. Spira-Solomon, James E. Penner-Hahn, Keith O. Hodgson, Edward I. SolomonCite this: Am. Chem. Soc. 1987, 109, 21, 6433–6442Publication Date (Print):October 1, 1987Publication History Published online1 May 2002Published inissue 1 October...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolid Phase Peptide SynthesisKeith HodgsonCite this: J. Med. Chem. 1970, 13, 1, 168Publication Date (Print):January 1970Publication History Published online7 January 2004Published inissue 1 1970https://pubs.acs.org/doi/10.1021/jm00295a901https://doi.org/10.1021/jm00295a901research-articleACS PublicationsRequest reuse permissionsArticle Views975Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text...
A novel application of x-ray absorption spectroscopy has provided structural information for ions sorbed at oxide-water interfaces. As an example, in situ extended fine structure (EXAFS) measurements adsorbed selenate and selenite α-FeOOH(goethite)—water interface have been performed; these show that forms a weakly bonded, outer-sphere complex strongly inner-sphere complex. The ion is bonded directly to the goethite surface bidentate fashion with two iron atoms 3.38 angstroms from selenium...
Biomimetic functional models of the mononuclear copper enzyme galactose oxidase are presented that catalytically oxidize benzylic and allylic alcohols to aldehydes with O 2 under mild conditions. The mechanistic fidelity between natural system is pronounced. Modest structural mimicry proves sufficient transfer an unusual ligand-based radical mechanism, previously unprecedented outside protein matrix, a simple chemical system.
We report the results of multiple scattered wave SCF X-alpha calculations one-electron cross section for K-shell photoabsorption in molecular complexes MoO4−−, CrO4−−, and MoS4−−. show that method can successfully account energy separations relative sections spectral features both below above ionization threshold. Furthermore, we show: (a) first fairly intense peak on low side rising edge molybdate chromate is due to a dipole allowed transition bound antibonding state mainly nd character...
We demonstrate a new approach for utilizing CuI coordination complexes as emissive layers in organic light-emitting diodes that involves situ codeposition of and 3,5-bis(carbazol-9-yl)pyridine (mCPy). With simple three-layer device structure, pure green electroluminescence at 530 nm from Cu(I) complex was observed. A maximum luminance external quantum efficiency (EQE) 9700 cd/m2 4.4%, respectively, were achieved. The luminescent species identified [CuI(mCPy)2]2 on the basis photophysical...
Significance Activation of the O-O bond in dioxygen is difficult but fundamental biology. Nature has evolved several strategies to achieve this, often including copper as an enzyme cofactor. Copper-dependent enzymes usually use more than one metal activate O 2 by multielectron reduction, recently it was discovered that cellulose and chitin degrading polysaccharide monooxygenase only a single Cu center for catalysis, reaction great interest biofuel industries. To understand this reactivity,...
Structural genomics is emerging as a principal approach to define protein structure-function relationships. To apply this on genomic scale, novel methods and technologies must be developed determine large numbers of structures. We describe the design implementation high-throughput structural pipeline its application proteome thermophilic bacterium Thermotoga maritima. By using pipeline, we successfully cloned attempted expression 1,376 predicted 1,877 genes (73%) have identified...
We have imaged a 2D buried Ni nanostructure at 8 nm resolution using coherent x-ray diffraction and the oversampling phasing method. By employing 3D imaging reconstruction algorithm, for first time we experimentally determined structure of noncrystalline nanostructured material 50 resolution. The is currently limited by exposure computing power, while ultimate wavelengths. believe these results pave way development atomic microscopy.
The binuclear copper enzyme tyrosinase activates O2 to form a mu-eta2:eta2-peroxodicopper(II) complex, which oxidizes phenols catechols. Here, synthetic with an absorption spectrum similar that of the enzymatic active oxidant, is reported rapidly hydroxylate phenolates at -80 degrees C. Upon phenolate addition extreme temperature in solution (-120 C), reactive intermediate consistent bis-mu-oxodicopper(III)-phenolate O-O bond fully cleaved, observed experimentally. subsequent hydroxylation...
Ligand K-edge X-ray absorption spectroscopy (XAS) is a new experimental probe of the covalency metal−ligand bond. The intensity ligand pre-edge feature proportional to mixing orbitals into metal d orbitals. methodology determine covalencies in one-electron (hole) and many-electron systems described demonstrated for series tetrachlorides [MCl4]n-, tetrathiolates [M(SR)4]n-, dimeric iron−sulfur (Fe−S) clusters [Fe2S2(SR)4]2-. It then applied blue Cu proteins, CuA site, hydrogen bonding Fe−S...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTX-ray absorption spectroscopic studies of the blue copper site: metal and ligand K-edge to probe origin EPR hyperfine splitting in plastocyaninSusan E. Shadle, James Penner-Hahn, Harvey J. Schugar, Britt Hedman, Keith O. Hodgson, Edward I. SolomonCite this: Am. Chem. Soc. 1993, 115, 2, 767–776Publication Date (Print):January 1, 1993Publication History Published online1 May 2002Published inissue 1 January...
The multicopper oxidases contain at least four copper atoms and catalyze the four-electron reduction of O2 to H2O a trinuclear cluster. An intermediate, termed native has been trapped by rapid freeze-quench technique from Rhus vernicifera laccase when fully reduced form reacts with dioxygen. This intermediate had described as an oxygen-radical bound cluster one Cu site reduced. XAS, however, shows that all are oxidized in this intermediate. A combination EXAFS, multifrequency EPR, VTVH MCD...
We report the first experimental recording, to our knowledge, of diffraction pattern from intact Escherichia coli bacteria using coherent x-rays with a wavelength 2 Å. By oversampling phasing method, real space image at resolution 30 nm was directly reconstructed pattern. An R factor used for characterizing quality reconstruction in range 5%, which demonstrated reliability process. The distribution proteins inside labeled manganese oxide has been identified and this confirmed by fluorescence...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural characterization of horseradish peroxidase using EXAFS spectroscopy. Evidence for Fe = O ligation in compounds I and IIJames E. Penner-Hahn, Kim. Smith Eble, Thomas J. McMurry, Mark. Renner, Alan L. Balch, John T. Groves, H. Dawson, Keith O. HodgsonCite this: Am. Chem. Soc. 1986, 108, 24, 7819–7825Publication Date (Print):November 1, 1986Publication History Published online1 May 2002Published inissue 1 November...
Distinct spectral features at the Fe L-edge of two compounds K3[Fe(CN)6] and K4[Fe(CN)6] have been identified characterized as arising from contributions ligand π* orbitals due to metal-to-ligand back-bonding. In addition, energy shifts total intensities allow changes in field effective nuclear charge be determined. It is found that term dominates edge shift. The results experimental analysis were compared BP86 DFT calculations. overall agreement between calculations experiment good;...