Metabolic Regulation of Nitrogen Fixation in Rhodospirillum rubrum and Evidence for an Energy-Dependent Ammonium Transport System

  • H. Wang
  • A. Norén
  • S. Nordlund
Part of the Current Plant Science and Biotechnology in Agriculture book series (PSBA, volume 42)

In photosynthetic R. rubrum, nitrogenase is tightly controlled at both the transcriptional and metabolic level. Nitrogenase activity is regulated by reversible ADP-ribosylation in response to external “switch-off” effectors. In response to a sudden fixed-N increase or energy depletion, the Fe protein is covalently modified by DRAT to inhibit nitrogenase activity. When the fixed-N is metabolized or the energy status of the cell is restored, DRAG removes the ADP-ribose moiety, activating nitrogenase (Nordlund and Ludden, 2004). Two different signal-transduction pathways appear to lead to nitrogen and energy “switch-off” with the pathways merging at or before affecting DRAT/DRAG activities.

Keywords

Respiration Photosynthesis Glutamine Azospirillum Azotobacter 

Copyright information

© Springer Science + Business Media B.V. 2008

Authors and Affiliations

  • H. Wang
    • 1
  • A. Norén
    • 1
  • S. Nordlund
    • 1
  1. 1.Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden

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