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Electron transfer in native and transition state complexes of nitrogenase

Reference	BBS/E/J/0000A017
Principal Investigator / Supervisor	Professor Barry Smith
Co-Investigators / Co-Supervisors
Institution	John Innes Centre
Department	John Innes Centre Department
Funding type	Research
Value (£)	15,115
Status	Completed
Type	Institute Project
Start date	30/03/2001
End date	31/12/2003
Duration	33 months

Abstract

The nitrogenase reaction cycle is thought to require the transient formation and dissociation of a complex between the Fe protein and the MoFe protein. Most previous mechanistic studies have utilized artificial electron donors. We plan to characterize the kinetics of nitrogenase interactions with flavodoxin, a natural electron donor, to determine whether dissociation is obligatory with this reductant. Electron transfer is facilitated by several rapid conformational changes in both nitrogenase proteins. Aluminium fluoride or beryllium fluoride anions stabilize nucleotide-G protein complexes by mimicking the terminal phosphate ion of ATP and preventing dissociation of the complex. We propose to study electron transfer and the accompanying conformational changes in beryllium fluoride and aluminium fluoride-stabilized nitrogenase complexes. Photochemical donor systems capable of reducing the Fe protein by one (eosin-NADH) or two electrons (DBF-NADH) and flavodoxin will be employed to reduce the free proteins and stabilized, non-dissociating complexes. In addition, complexes containing GDP and other dinucleotides which do not support substrate reduction will be made and characterized to ascertain the conformational state of the inhibited system. The aim of these experiments is to describe the detailed mechanism of electron transfer and energy transduction by the nitrogenase enzyme system with a view towards improvement in the efficiency of the agriculturally important biological nitrogen fixation process

Summary

unavailable

Committee	Closed Committee - Biomolecular Sciences (BMS)
Research Topics	X – not assigned to a current Research Topic
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

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