title: DNA replicases from a bacterial perspective.
abstract: Bacterial replicases are complex, tripartite replicative machines. They contain a polymerase, polymerase III (Pol III), a β₂ processivity factor, and a DnaX complex ATPase that loads β₂ onto DNA and chaperones Pol III onto the newly loaded β₂. Bacterial replicases are highly processive, yet cycle rapidly during Okazaki fragment synthesis in a regulated way. Many bacteria encode both a full-length τ and a shorter γ form of DnaX by a variety of mechanisms. γ appears to be uniquely placed in a single position relative to two τ protomers in a pentameric ring. The polymerase catalytic subunit of Pol III, α, contains a PHP domain that not only binds to a prototypical ε Mg²⁺-dependent exonuclease, but also contains a second Zn²⁺-dependent proofreading exonuclease, at least in some bacteria. This review focuses on a critical evaluation of recent literature and concepts pertaining to the above issues and suggests specific areas that require further investigation.
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA. charles.mchenry@colorado.edu
authors.forename: Charles S
authors.initials: CS
authors.lastname: McHenry
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004258:DNA Polymerase III / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D011487:Protein Conformation
chemical_list: D001426:Bacterial Proteins; C022262:Okazaki fragments; D004247:DNA; C023140:DNA replicase; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase