One major element of our program is the development of electron- nuclear double resonance (endor) spectroscopy as an essential tool in determining metalloenzyme structure and function. To this end we will develop Q-Band (35 GHz) endor as a standard measurement technique in metallobiochemistry because it will prevent proton- endor signals from obscuring the resonances of constitutive nuclei (14,15N, 13C, 17O, 57Fe, 33S) and will reduce requirements 10-20 fold, opening new prospects for studying scarce or isotopically labelled proteins. Q-Band, CW and pulsed-X Band, and double endor techniques will be applied to the study of a wide range of enzymes active sites, including the CuA and CuB sites of cytochrome oxidases, the atypical (2Fe, 2S) center of Rieske-type respiratory proteins and enzymes, and the multi-metal clusters of carbon monoxide dehydrogenase. In the second major element we employ metal-substituted hemoproteins to elucidate the factors regulating long-range electron transfer within protein-protein complexes. Mixed-metal, (M,M') hemoglobin hybrids, M = Zn,Mg, M' = Fe, Mn, Co, provide the ideal system for examining inter-protein electron transfer where the two redox centers are rigidly held within a structure that can be crystallographically determined to high precision. The complex cytochrome c peroxidase (CcP) and its physiological partner, cytochrome c (Cc), will be used to examine the role of the docking interface in regulating recognition and function, as well as the role of the protein matrix in modulating electron transfer. We shall use Cc from multiple species to explore the evolutionary matching of the interface with Zn and Mg-substituted CcP. Variants of CcP and of the Cc from yeast, drosophila, and rat that have been produced by site-specific mutagenesis will be used to explore the regulatory role of single amino acids and clusters both at the protein-protein interface and in the heme crevice. The complexes between cytochrome P450-cam with putadaredoxin and cytochrome b5 will provide a parallel system for study.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37HL013531-23
Application #
2214752
Study Section
Special Emphasis Panel (NSS)
Project Start
1979-01-01
Project End
1998-12-31
Budget Start
1995-01-01
Budget End
1995-12-31
Support Year
23
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Northwestern University at Chicago
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
City
Evanston
State
IL
Country
United States
Zip Code
60201
Davydov, Roman; Im, Sangchoul; Shanmugam, Muralidharan et al. (2016) Role of the Proximal Cysteine Hydrogen Bonding Interaction in Cytochrome P450 2B4 Studied by Cryoreduction, Electron Paramagnetic Resonance, and Electron-Nuclear Double Resonance Spectroscopy. Biochemistry 55:869-83
Davydov, Roman; Labby, Kristin Jansen; Chobot, Sarah E et al. (2014) Enzymatic and cryoreduction EPR studies of the hydroxylation of methylated N(?)-hydroxy-L-arginine analogues by nitric oxide synthase from Geobacillus stearothermophilus. Biochemistry 53:6511-9
Ortony, Julia H; Newcomb, Christina J; Matson, John B et al. (2014) Internal dynamics of a supramolecular nanofibre. Nat Mater 13:812-6
Hoffman, Brian M; Lukoyanov, Dmitriy; Yang, Zhi-Yong et al. (2014) Mechanism of nitrogen fixation by nitrogenase: the next stage. Chem Rev 114:4041-62
Lukoyanov, Dmitriy; Yang, Zhi-Yong; Duval, Simon et al. (2014) A confirmation of the quench-cryoannealing relaxation protocol for identifying reduction states of freeze-trapped nitrogenase intermediates. Inorg Chem 53:3688-93
Hoffman, Brian M; Lukoyanov, Dmitriy; Dean, Dennis R et al. (2013) Nitrogenase: a draft mechanism. Acc Chem Res 46:587-95
Sharma, Ajay; Gaidamakova, Elena K; Matrosova, Vera Y et al. (2013) Responses of Mn2+ speciation in Deinococcus radiodurans and Escherichia coli to ?-radiation by advanced paramagnetic resonance methods. Proc Natl Acad Sci U S A 110:5945-50
Davydov, Roman; Dawson, John H; Perera, Roshan et al. (2013) The use of deuterated camphor as a substrate in (1)H ENDOR studies of hydroxylation by cryoreduced oxy P450cam provides new evidence of the involvement of compound I. Biochemistry 52:667-71
Yang, Zhi-Yong; Khadka, Nimesh; Lukoyanov, Dmitriy et al. (2013) On reversible H2 loss upon N2 binding to FeMo-cofactor of nitrogenase. Proc Natl Acad Sci U S A 110:16327-32
Davydov, Roman M; McLaughlin, Matthew P; Bill, Eckhard et al. (2013) Generation of high-spin iron(I) in a protein environment using cryoreduction. Inorg Chem 52:7323-5

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