Nitrogenase is a complex metalloenzyme that catalyzes one of the most remarkable chemical transformations in biological systems: the nucleotide-dependent reduction of atmospheric dinitrogen to bioavailable ammonia. There is an outstanding interest in decoding the assembly mechanism of nitrogenase, not only because of its significant relevance to nitrogenase-specific reactions, but also because of its tremendous implication for general metalloprotein biogenesis. Here we propose to greatly expand our understanding of the nitrogenase assembly process by combined genetic, biochemical, spectroscopic and structural approaches. The MoFe protein of the molybdenum nitrogenase of Azotobacter vinelandii will be the focus of the proposed investigation. Through our proposed studies, we expect to further refine the biosynthetic pathways of MoFe protein and its associated clusters, a continuous effort with an ultimate goal to unravel the molecular mechanism of nitrogenase assembly. Furthermore, using nitrogenase as a model system, we also hope to provide general themes of biological metal cluster assembly, which may, in the long run, prove instrumental in developing successful strategies for the chemical synthesis of complex metalloclusters. .

Public Health Relevance

Nitrogenase catalyzes the transformation of atmospheric dinitrogen to bioavailable ammonia, thereby supplying the reduced nitrogen, an essential component of nucleic acids and proteins, for the existence of human population. This particular proposal deals with the assembly of nitrogenase MoFe protein and its associated metalloclusters and the outcome of these studies will hopefully provide general themes of biological metal cluster assembly and facilitate future development of cost-efficient strategies for the chemical synthesis of catalytically active metalloclusters. As such, our proposed research may have additional economic value in addition to its intrinsic relevancy to human health.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
3R01GM067626-06A1S1
Application #
7930293
Study Section
Macromolecular Structure and Function A Study Section (MSFA)
Program Officer
Fabian, Miles
Project Start
2009-09-30
Project End
2010-08-31
Budget Start
2009-09-30
Budget End
2010-08-31
Support Year
6
Fiscal Year
2009
Total Cost
$33,544
Indirect Cost
Name
University of California Irvine
Department
Biochemistry
Type
Schools of Arts and Sciences
DUNS #
046705849
City
Irvine
State
CA
Country
United States
Zip Code
92697
Rettberg, Lee A; Wilcoxen, Jarett; Lee, Chi Chung et al. (2018) Probing the coordination and function of Fe4S4 modules in nitrogenase assembly protein NifB. Nat Commun 9:2824
Tanifuji, Kazuki; Lee, Chi Chung; Sickerman, Nathaniel S et al. (2018) Tracing the 'ninth sulfur' of the nitrogenase cofactor via a semi-synthetic approach. Nat Chem 10:568-572
Rupnik, Kresimir; Lee, Chi Chung; Hu, Yilin et al. (2018) A VTVH MCD and EPR Spectroscopic Study of the Maturation of the ""Second"" Nitrogenase P-Cluster. Inorg Chem 57:4719-4725
Sickerman, Nathaniel S; Rettberg, Lee A; Lee, Chi Chung et al. (2017) Cluster assembly in nitrogenase. Essays Biochem 61:271-279
Fay, Aaron W; Blank, Michael A; Rebelein, Johannes G et al. (2016) Assembly scaffold NifEN: A structural and functional homolog of the nitrogenase catalytic component. Proc Natl Acad Sci U S A 113:9504-8
Hu, Yilin; Ribbe, Markus W (2016) Maturation of nitrogenase cofactor-the role of a class E radical SAM methyltransferase NifB. Curr Opin Chem Biol 31:188-94
Lee, Chi Chung; Sickerman, Nathaniel S; Hu, Yilin et al. (2016) YedY: A Mononuclear Molybdenum Enzyme with a Redox-Active Ligand? Chembiochem 17:453-5
Lee, Chi Chung; Fay, Aaron W; Weng, Tsu-Chien et al. (2015) Uncoupling binding of substrate CO from turnover by vanadium nitrogenase. Proc Natl Acad Sci U S A 112:13845-9
Wiig, Jared A; Hu, Yilin; Ribbe, Markus W (2015) Refining the pathway of carbide insertion into the nitrogenase M-cluster. Nat Commun 6:8034
Cahn, Jackson K B; Brinkmann-Chen, Sabine; Spatzal, Thomas et al. (2015) Cofactor specificity motifs and the induced fit mechanism in class I ketol-acid reductoisomerases. Biochem J 468:475-84

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