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PDBsum entry 2hpm
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References listed in PDB file
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Key reference
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Title
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The structure of t. Aquaticus DNA polymerase III is distinct from eukaryotic replicative DNA polymerases.
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Authors
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S.Bailey,
R.A.Wing,
T.A.Steitz.
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Ref.
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Cell, 2006,
126,
893-904.
[DOI no: ]
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PubMed id
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Abstract
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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.
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Figure 1.
Figure 1. A Representative Region of Electron Density
Unbiased F[o] − F[c] electron density map contoured at 3σ.
The residues, which are represented as sticks, were omitted from
the map calculation.
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Figure 2.
Figure 2. Crystal Structure of Taq DNA Polymerase III α
Subunit
(Top middle) A schematic diagram of the domain
positions in the PolIIIα sequence. The domains are labeled and
colored as follows: the PHP domain in yellow, the palm in
magenta, the thumb in green, the fingers in light blue, the β
binding domain in orange, and the CTD in red. (Center) Two
orthogonal views of the surface of PolIIIα colored as in the
schematic above. Ribbon diagrams of the individual domains are
shown around the outside.
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The above figures are
reprinted
by permission from Cell Press:
Cell
(2006,
126,
893-904)
copyright 2006.
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