2HPI: Eubacterial And Eukaryotic Replicative Dna Polymerases Are Not Homologous: X-ray Structure Of Dna Polymerase Iii

The crystal structure of Thermus aquaticus DNA polymerase III alpha subunit reveals that the structure of the catalytic domain of the eubacterial replicative polymerase is unrelated to that of the eukaryotic replicative polymerase but rather belongs to the Polbeta-like nucleotidyltransferase superfamily. A model of the polymerase complexed with both DNA and beta-sliding clamp interacting with a reoriented binding domain and internal beta binding site was constructed that is consistent with existing biochemical data. Within the crystal, two C-terminal domains are interacting through a surface that is larger than many dimer interfaces. Since replicative polymerases of eubacteria and eukaryotes/archaea are not homologous, the nature of the replicative polymerase in the last common ancestor is unknown. Although other possibilities have been proposed, the plausibility of a ribozyme DNA polymerase should be considered.
PDB ID: 2HPIDownload
MMDB ID: 41676
PDB Deposition Date: 2006/7/17
Updated in MMDB: 2012/12
Experimental Method:
x-ray diffraction
Resolution: 3  Å
Source Organism:
Similar Structures:
Biological Unit for 2HPI: monomeric; determined by author and by software (PQS)
Molecular Components in 2HPI
Label Count Molecule
Protein (1 molecule)
DNA Polymerase III Alpha Subunit
Molecule annotation
Chemicals (6 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB