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Clarke, Tom 
ORCID: https://orcid.org/0000-0002-6234-1914, Fairhurst, Shirley, Lowe, David J., Watmough, Nick and Eady, Robert R.
(2011)
Electron transfer and half-reactivity in nitrogenase.
Biochemical Society Transactions, 39 (1).
pp. 201-206.
ISSN 0300-5127
Abstract
Nitrogenase is a globally important enzyme that catalyses the reduction of atmospheric dinitrogen into ammonia and is thus an important part of the nitrogen cycle. The nitrogenase enzyme is composed of a catalytic molybdenum–iron protein (MoFe protein) and a protein containing an [Fe4–S4] cluster (Fe protein) that functions as a dedicated ATP-dependent reductase. The current understanding of electron transfer between these two proteins is based on stopped-flow spectrophotometry, which has allowed the rates of complex formation and electron transfer to be accurately determined. Surprisingly, a total of four Fe protein molecules are required to saturate one MoFe protein molecule, despite there being only two well-characterized Fe-protein-binding sites. This has led to the conclusion that the purified Fe protein is only half-active with respect to electron transfer to the MoFe protein. Studies on the electron transfer between both proteins using rapid-quench EPR confirmed that, during pre-steady-state electron transfer, the Fe protein only becomes half-oxidized. However, stopped-flow spectrophotometry on MoFe protein that had only one active site occupied was saturated by approximately three Fe protein equivalents. These results imply that the Fe protein has a second interaction during the initial stages of mixing that is not involved in electron transfer.
| Item Type: | Article |
|---|---|
| Faculty \ School: | Faculty of Science > School of Biological Sciences |
| UEA Research Groups: | Faculty of Science > Research Groups > Molecular Microbiology Faculty of Science > Research Centres > Centre for Molecular and Structural Biochemistry Faculty of Science > Research Groups > Energy Materials Laboratory |
| Depositing User: | Users 2731 not found. |
| Date Deposited: | 14 Feb 2011 14:03 |
| Last Modified: | 21 Apr 2023 06:30 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/21344 |
| DOI: | 10.1042/BST0390201 |
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