PII Signal Transduction Proteins: Pivotal Players in Post-Translational Control of Nitrogenase Activity

Microbiology. 2012 Jan;158(Pt 1):176-190. doi: 10.1099/mic.0.049783-0.


The fixation of atmospheric nitrogen by the prokaryotic enzyme nitrogenase is an energy- expensive process and consequently it is tightly regulated at a variety of levels. In many diazotrophs this includes post-translational regulation of the enzyme's activity, which has been reported in both bacteria and archaea. The best understood response is the short-term inactivation of nitrogenase in response to a transient rise in ammonium levels in the environment. A number of proteobacteria species effect this regulation through reversible ADP-ribosylation of the enzyme, but other prokaryotes have evolved different mechanisms. Here we review current knowledge of post-translational control of nitrogenase and show that, for the response to ammonium, the P(II) signal transduction proteins act as key players.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Bacteria / enzymology*
  • Bacteria / genetics
  • Bacteria / metabolism
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Gene Expression Regulation, Bacterial
  • Nitrogenase / genetics
  • Nitrogenase / metabolism*
  • PII Nitrogen Regulatory Proteins / genetics
  • PII Nitrogen Regulatory Proteins / metabolism*
  • Protein Processing, Post-Translational
  • Signal Transduction*


  • Bacterial Proteins
  • PII Nitrogen Regulatory Proteins
  • Nitrogenase