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Steric Control of the Hi-CO MoFe Nitrogenase Complex Revealed by Stopped-Flow Infrared Spectroscopy

Authors

  • Dr. Zhi-Yong Yang,

    1. Department of Chemistry and Biochemistry, UMC 0300 Old Main Hill, Utah State University, Logan, UT 84322 (USA)
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  • Prof. Lance C. Seefeldt,

    1. Department of Chemistry and Biochemistry, UMC 0300 Old Main Hill, Utah State University, Logan, UT 84322 (USA)
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  • Prof. Dennis R. Dean,

    1. Department of Biochemistry, Virginia Polytechnic Institute and State University, 110 Fralin Hall, Blacksburg, VA 24061 (USA)
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  • Prof. Stephen P. Cramer,

    1. Department of Applied Science, University of California, Davis, One Shields Avenue, Davis, CA 95616 (USA), Fax: (+1) 530-752-2444
    2. Advanced Biological and Environmental X-ray Facility, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 6R2100, Berkeley, CA 94720 (USA)
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  • Dr. Simon J. George

    Corresponding author
    1. Department of Applied Science, University of California, Davis, One Shields Avenue, Davis, CA 95616 (USA), Fax: (+1) 530-752-2444
    2. Advanced Biological and Environmental X-ray Facility, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 6R2100, Berkeley, CA 94720 (USA)
    • Department of Applied Science, University of California, Davis, One Shields Avenue, Davis, CA 95616 (USA), Fax: (+1) 530-752-2444
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  • This work was funded by the NIH (GM-65440; S.P.C. and GM-59087; L.C.S. and D.R.D.), the NSF (CHE-0745353; S.P.C.), and the DOE Office of Biological and Environmental Research (S.P.C.). The authors thank Celestine Grady-Smith for experimental assistance.

Abstract

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Revealing kinetics: For the α-70 residue of MoFe nitrogenase in Azotobacter vinelandii the impact of substitution on the CO coordination to the enzyme's active center was studied by using stopped-flow IR spectroscopy. The results suggest that in all cases the CO ligand binds to the Fe 2-3-6-7 face of the FeMo-cofactor (see picture).

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