Bacterial replicases and related polymerases

Curr Opin Chem Biol. 2011 Oct;15(5):587-94. doi: 10.1016/j.cbpa.2011.07.018. Epub 2011 Aug 19.


Bacterial replicases are complex, tripartite replicative machines. They contain a polymerase, Pol III, a β(2) processivity factor and a DnaX complex ATPase that loads β(2) onto DNA and chaperones Pol III onto the newly loaded β(2). Many bacteria encode both a full length τ and a shorter γ form of DnaX by a variety of mechanisms. The polymerase catalytic subunit of Pol III, α, contains a PHP domain that not only binds to prototypical ɛ Mg(2+)-dependent exonuclease, but also contains a second Zn(2+)-dependent proofreading exonuclease, at least in some bacteria. Replication of the chromosomes of low GC Gram-positive bacteria require two Pol IIIs, one of which, DnaE, appears to extend RNA primers a only short distance before handing the product off to the major replicase, PolC. Other bacteria encode a second Pol III (ImuC) that apparently replaces Pol V, required for induced mutagenesis in E. coli. Approaches that permit simultaneous biochemical screening of all components of complex bacterial replicases promise inhibitors of specific protein targets and reaction stages.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Adenosine Triphosphatases / chemistry
  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / metabolism*
  • Bacteria / chemistry
  • Bacteria / genetics
  • Bacteria / metabolism*
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • DNA / genetics
  • DNA / metabolism
  • DNA Polymerase III / chemistry
  • DNA Polymerase III / genetics
  • DNA Polymerase III / metabolism*
  • DNA Replication / genetics*
  • Exodeoxyribonucleases / genetics
  • Exodeoxyribonucleases / metabolism
  • Isoenzymes / chemistry
  • Isoenzymes / genetics
  • Isoenzymes / metabolism*
  • Models, Molecular
  • Molecular Chaperones / chemistry
  • Molecular Chaperones / genetics
  • Molecular Chaperones / metabolism
  • Protein Binding / genetics
  • Protein Structure, Tertiary
  • Protein Subunits / chemistry
  • Protein Subunits / genetics
  • Protein Subunits / metabolism*


  • Bacterial Proteins
  • Isoenzymes
  • Molecular Chaperones
  • Protein Subunits
  • DNA
  • DNA Polymerase III
  • Exodeoxyribonucleases
  • Adenosine Triphosphatases