This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. We propose here complementary multi-edge X-ray absorption spectroscopic investigations of site-differentiated cubane-type Mo/Fe/S clusters for developing synthetic targets for homogeneous dinitrogen reduction processes. These targets can be considered as biomimetic compounds of the iron-molybdenum cofactor (FeMo-co) of nitrogenase. We plan to accomplish this in three stages. First, we will characterize cubane type Mo/Fe/S cluster with systematically varied S and Se ligand environments in oxidized and reduced states using sulfide, selenide, diethyldithio carbamate (DTC), and diethyldiseleno carbamate (DSC) ligands. Second, we will modify the terminal ligands around Fe targeting to stabilize low valent states of Fe that likely be poised toward activating dinitrogen because of the increased nucleophilicity of the cluster core. Third we perturb the coordination environments around Mo to thoroughly assess the ligand field effect on the electronic and geometric structures of the clusters. We plan to take advantage of complementarity of XAS data at the Fe K-, Fe L-, Mo L-, Cl K-, Se K- and S K-edges to generate desirable structural properties of future clusters. Recent beamline development at BL4-3 now allows for collection of S and Cl EXAFS, which in combination with Fe/Mo/S EXAFS can provide more reliable fits of geometric structure. XANES analysis of pre-edge and rising-edge features of Fe L-edge and S K-edge spectra provides electronic structural information about effective nuclear charges, oxidation and spin states of metal/ligand centers, orbital compositions, ligand-field splitting of metal centers, and possible non-innocent behavior of ligands. Separation of overlapping S K- and Mo L-edges will be achieved by utilizing Se derivatives. In addition to the potential of making new biomimetic compounds insights from the proposed experiments will have impact on the understanding of the controversial role of the Mo-site in activation of dinitrogen.

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
5P41RR001209-32
Application #
8362365
Study Section
Special Emphasis Panel (ZRG1-BCMB-P (40))
Project Start
2011-03-01
Project End
2012-02-29
Budget Start
2011-03-01
Budget End
2012-02-29
Support Year
32
Fiscal Year
2011
Total Cost
$4,384
Indirect Cost
Name
Stanford University
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
009214214
City
Stanford
State
CA
Country
United States
Zip Code
94305
Remesh, Soumya G; Andreatta, Massimo; Ying, Ge et al. (2017) Unconventional Peptide Presentation by Major Histocompatibility Complex (MHC) Class I Allele HLA-A*02:01: BREAKING CONFINEMENT. J Biol Chem 292:5262-5270
VanderLinden, Ryan T; Hemmis, Casey W; Yao, Tingting et al. (2017) Structure and energetics of pairwise interactions between proteasome subunits RPN2, RPN13, and ubiquitin clarify a substrate recruitment mechanism. J Biol Chem 292:9493-9504
Zhang, Haonan; Qiao, Anna; Yang, Dehua et al. (2017) Structure of the full-length glucagon class B G-protein-coupled receptor. Nature 546:259-264
Niedzialkowska, Ewa; Mruga?a, Beata; Rugor, Agnieszka et al. (2017) Optimization of overexpression of a chaperone protein of steroid C25 dehydrogenase for biochemical and biophysical characterization. Protein Expr Purif 134:47-62
de Vries, Robert P; Tzarum, Netanel; Peng, Wenjie et al. (2017) A single mutation in Taiwanese H6N1 influenza hemagglutinin switches binding to human-type receptors. EMBO Mol Med 9:1314-1325
Tolbert, William D; Gohain, Neelakshi; Alsahafi, Nirmin et al. (2017) Targeting the Late Stage of HIV-1 Entry for Antibody-Dependent Cellular Cytotoxicity: Structural Basis for Env Epitopes in the C11 Region. Structure 25:1719-1731.e4
Yoon, Chun Hong; DeMirci, Hasan; Sierra, Raymond G et al. (2017) Se-SAD serial femtosecond crystallography datasets from selenobiotinyl-streptavidin. Sci Data 4:170055
Warelow, Thomas P; Pushie, M Jake; Cotelesage, Julien J H et al. (2017) The active site structure and catalytic mechanism of arsenite oxidase. Sci Rep 7:1757
Tzarum, Netanel; de Vries, Robert P; Peng, Wenjie et al. (2017) The 150-Loop Restricts the Host Specificity of Human H10N8 Influenza Virus. Cell Rep 19:235-245
Hettle, Andrew; Fillo, Alexander; Abe, Kento et al. (2017) Properties of a family 56 carbohydrate-binding module and its role in the recognition and hydrolysis of ?-1,3-glucan. J Biol Chem 292:16955-16968

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