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Crystallographic structure of the nitrogenase iron protein from Azotobacter vinelandii

Georgiadis, M. M. and Komiya, H. and Chakrabarti, P. and Woo, D. and Kornuc, J. J. and Rees, D. C. (1992) Crystallographic structure of the nitrogenase iron protein from Azotobacter vinelandii. Science, 257 (5077). pp. 1653-1659. ISSN 0036-8075. doi:10.1126/science.1529353.

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The nitrogenase enzyme system catalyzes the ATP (adenosine triphosphate)-dependent reduction of dinitrogen to ammonia during the process of nitrogen fixation. Nitrogenase consists of two proteins: the iron (Fe)-protein, which couples hydrolysis of ATP to electron transfer, and the molybdenum-iron (MoFe)-protein, which contains the dinitrogen binding site. In order to address the role of ATP in nitrogen fixation, the crystal structure of the nitrogenase Fe-protein from Azotobacter vinelandii has been determined at 2.9 angstrom (A) resolution. Fe-protein is a dimer of two identical subunits that coordinate a single 4Fe:4S cluster. Each subunit folds as a single alpha/beta type domain, which together symmetrically ligate the surface exposed 4Fe:4S cluster through two cysteines from each subunit. A single bound ADP (adenosine diphosphate) molecule is located in the interface region between the two subunits. Because the phosphate groups of this nucleotide are approximately 20 A from the 4Fe:4S cluster, it is unlikely that ATP hydrolysis and electron transfer are directly coupled. Instead, it appears that interactions between the nucleotide and cluster sites must be indirectly coupled by allosteric changes occurring at the subunit interface. The coupling between protein conformation and nucleotide hydrolysis in Fe-protein exhibits general similarities to the H-Ras p21 and recA proteins that have been recently characterized structurally. The Fe-protein structure may be relevant to the functioning of other biochemical energy-transducing systems containing two nucleotide-binding sites, including membrane transport proteins.

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Rees, D. C.0000-0003-4073-1185
Additional Information:© 1992 American Association for the Advancement of Science. 19 June 1992; Accepted 18 August 1992. This work was initiated in the laboratory of J. B. Howard, whose advice and encouragement was significant at all stages of the project. The contributions of B. T. Hsu, A. J. Chirino, L. Joshua-Tor, J. L. Schlessman, D. E. Malerba and the Caltech Structural Biology Group, D. S. Eisenberg and the UCLA Structural Biology Group, D. H. Burke, L. C. Davis, H. Hope, and S.-H. Kim are gratefully appreciated. C. D. Stout suggested the use of thiomalates as heavy atom derivatives, and T. Schaak provided the myochrisine. The rotation camera facility at the Stanford Synchrotron Radiation Laboratory is supported by the Department of Energy, Office of Basic Energy Sciences, and the National -Institutes of Health Biomedical Resource Technology Program, Division of Research Resources. Coordinates will be deposited in the Brookhaven Protein Data Bank, and are available by E-mail (REES@CITRAY.CALTECH.EDU). Supported by USPHS grant GM45162 and an NSF PYI award, with instrumentation funded in part by the Beckman Institute and the Joseph Irvine Equipment Fund.
Funding AgencyGrant Number
Department of Energy (DOE)UNSPECIFIED
NIH Biomedical Technology Resource ProgramUNSPECIFIED
United States Public Health Service (USPHS)GM45162
Caltech Beckman InstituteUNSPECIFIED
Joseph Irvine Equipment FundUNSPECIFIED
Issue or Number:5077
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Official Citation:Georgiadis, M., Komiya, H., Chakrabarti, P., Woo, D., Kornuc, J., & Rees, D. (1992). Crystallographic structure of the nitrogenase iron protein from Azotobacter vinelandii. Science, 257(5077), 1653-1659. doi: 10.1126/science.1529353
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ID Code:54005
Deposited On:23 Jan 2015 02:15
Last Modified:10 Nov 2021 20:26

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