Affordable Access

Publisher Website

Redox properties and electron paramagnetic resonance spectroscopy of the transition state complex ofAzotobacter vinelandiinitrogenase

Authors
Journal
FEBS Letters
0014-5793
Publisher
Wiley Blackwell (John Wiley & Sons)
Publication Date
Volume
432
Identifiers
DOI: 10.1016/s0014-5793(98)00827-8
Keywords
  • Nitrogenase (Azotobacter Vinelandii)
  • Transition State Complex
  • Redox Potential
  • Electron Paramagnetic Resonance
Disciplines
  • Biology

Abstract

Abstract Nitrogenase is a two-component metalloenzyme that catalyzes a MgATP hydrolysis driven reduction of substrates. Aluminum fluoride plus MgADP inhibits nitrogenase by stabilizing an intermediate of the on-enzyme MgATP hydrolysis reaction. We report here the redox properties and electron paramagnetic resonance (EPR) signals of the aluminum fluoride-MgADP stabilized nitrogenase complex of Azotobacter vinelandii. Complex formation lowers the midpoint potential of the [4Fe-4S] cluster in the Fe protein. Also, the two-electron reaction of the unique [8Fe-7S] cluster in the MoFe protein is split in two one-electron reactions both with lower midpoint potentials. Furthermore, a change in spin-state of the two-electron oxidized [8Fe-7S] cluster is observed. The implications of these findings for the mechanism of MgATP hydrolysis driven electron transport within the nitrogenase protein complex are discussed.

There are no comments yet on this publication. Be the first to share your thoughts.