ABC-type amino acid uptake transporters Bgt and N-II of Anabaena sp. strain PCC 7120 share an ATPase subunit and are expressed in vegetative cells and heterocysts

Mol Microbiol. 2008 Mar;67(5):1067-80. doi: 10.1111/j.1365-2958.2008.06107.x. Epub 2008 Jan 17.


Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that can fix N(2) in differentiated cells called heterocysts. Anabaena open reading frames alr4167 and alr3187 encode, respectively, an ATPase subunit, BgtA, and a composite protein bearing periplasmic substrate-binding and transmembrane domains, BgtB, of an ABC-type high-affinity basic amino acid uptake transporter (Bgt). Open reading frame alr4167 is clustered with open reading frames alr4164, alr4165 and alr4166 that encode a periplasmic substrate-binding protein, NatF, and transmembrane proteins NatG and NatH respectively. The NatF, NatG, NatH and BgtA proteins constitute an ABC-type uptake transporter for acidic and neutral polar amino acids (N-II). The Bgt and N-II transport systems thus share the ATPase subunit, BgtA. These transporters together with the previously characterized ABC-type uptake transporter for proline and hydrophobic amino acids (N-I) account for more than 98% of the amino acid transport activity exhibited by Anabaena sp. strain PCC 7120. In contrast to N-I that is expressed only in vegetative cells, the Bgt and N-II systems are present in both vegetative cells and heterocysts. Whereas Bgt is dispensable for diazotrophic growth, N-II appears to contribute together with N-I to the diazotrophic physiology of this cyanobacterium.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / analysis
  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / metabolism*
  • Amino Acid Transport Systems / analysis
  • Amino Acid Transport Systems / genetics
  • Amino Acid Transport Systems / metabolism*
  • Amino Acids / metabolism
  • Anabaena / cytology
  • Anabaena / growth & development
  • Anabaena / metabolism*
  • Bacterial Proteins / analysis
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Biological Transport*
  • Conjugation, Genetic
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Microscopy, Confocal
  • Molecular Sequence Data
  • Mutation
  • Nitrogen Fixation
  • Protein Subunits / analysis
  • Protein Subunits / genetics
  • Protein Subunits / metabolism
  • Recombinant Fusion Proteins / analysis
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Substrate Specificity


  • Amino Acid Transport Systems
  • Amino Acids
  • Bacterial Proteins
  • Protein Subunits
  • Recombinant Fusion Proteins
  • Green Fluorescent Proteins
  • Adenosine Triphosphatases