Understanding Nitrogen Fixation in Bacteria


Nitrogen fixation is required for all forms of life, being essential for the biosynthesis of molecules that are used in creating plants and organisms.  Nitrogenase is the only known enzyme capable of performing this multi-electron reduction, and understanding how it does this conversion is of high importance also for the production of ammonia (as fertilizer), for energy efficiency (as industrial processes to produce ammonia consumes enormous amounts of energy), and for global warming (capturing N2).  The structure of the CO inhibitor bound to the FeMo-cofactor active site in nitrogenase at high resolution provides insight into a catalytic competent state, establishes the importance of a bridging S atom, and indicates how N2 might bind during turn-over. Stanford Synchrotron Radiation Lightsource.

Spatzal, K.A. Perez, O. Einsle, J.B. Howard, D.C. Rees, “Ligand binding to the FeMo-cofactor: Structures of CO-bound and reactivated nitrogenase” Science 345, 1620-1623 (2014), doi: 10.1126/science.1256679

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Funding Acknowledgements: Work supported by National Institutes of Health (NIH) grant GM45162 (D.C.R.), Deutsche Forschungsgemeinschaft grants EI-520/7 and RTG 1976, and European Research Council N-ABLE project (O.E.). Gordon and Betty Moore Foundation, Beckman Institute, and Sanofi-Aventis Bioengineering Research Program at Caltech: support of Molecular Observatory at Caltech and staff at Beamline 12–2, Stanford Synchrotron Radiation Lightsource (SSRL), for their assistance with data collection. SSRL is operated for the U.S. Department of Energy (DOE) Office of Science and supported by its Office of Biological and Environmental Research (OBER) and by the National Institutes of Health’s (NIH) National Institute of General Medical Sciences (NIGMS; P41GM103393) and National Center for Research Resources (NCRR; P41RR001209). Center for Environmental Microbial Interactions: support of microbiology research at Caltech. Coordinates and structure factors deposited in Protein Data Bank of the Research Collaboratory for Structural Bioinformatics, with IDs 4TKV (Av1-CO) and 4TKU (Av1 reactivated).