mrpA (all1838), a gene involved in alkali and Na(+) sensitivity, may also have a role in energy metabolism in the cyanobacterium Anabaena sp. strain PCC 7120

J Plant Physiol. 2009 Sep 15;166(14):1488-96. doi: 10.1016/j.jplph.2009.03.007. Epub 2009 May 1.

Abstract

Anabaena sp. PCC7120 contains a gene, mrpA (all1838), which forms part of a seven gene-cluster (all1843-all1837) with significant sequence similarity to bacterial operons that putatively code for a multicomponent cation/proton antiporter involved in alkaline pH adaptation and salt resistance. We previously showed that growth and photosynthesis were inhibited in a strain mutated in mrpA, denoted as PHB11, particularly at alkaline pH. Here, we show that respiration was also impaired in the mutant independently of the external pH. In addition, at high pH, less ATP and vegetative cell ferredoxin were present in PHB11, which also showed lower levels of ferredoxin-NADP(+) oxidoreductase (FNR). Ferredoxin and FNR are involved in the generation of reductant NADPH in cyanobacteria. These results suggest an energetic role of mrpA (and perhaps of the whole mrp-gene cluster) in Anabaena sp. PCC 7120 that is further supported by the significant similarity of putative Anabaena Mrp proteins to membrane subunits of complex I.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Anabaena / genetics*
  • Anabaena / metabolism*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / physiology*
  • Blotting, Western
  • Cell Respiration / genetics
  • Cell Respiration / physiology
  • Electrophoresis, Polyacrylamide Gel
  • Energy Metabolism / genetics*
  • Ferredoxin-NADP Reductase / genetics
  • Ferredoxin-NADP Reductase / metabolism
  • Ferredoxins / metabolism
  • Gene Expression Regulation, Bacterial / genetics
  • Gene Expression Regulation, Bacterial / physiology
  • Hydrogen-Ion Concentration
  • Multigene Family / genetics
  • Multigene Family / physiology
  • Mutation
  • Sodium / metabolism*

Substances

  • Bacterial Proteins
  • Ferredoxins
  • Adenosine Triphosphate
  • Sodium
  • Ferredoxin-NADP Reductase