DNA polymerase III beta subunit
SMART accession number:SM00480
Description: -
Interpro abstract (IPR001001):

DNA polymerase III is a complex, multichain holoenzyme responsible for most of the replicative synthesis in bacteria [ (PUBMED:8548826) ]. It functions by adding nucleotide triphosphate (dNTP) residues to the 5'-end of a growing DNA chain, using a complementary DNA as template. The elongation factor beta-clamp, also called beta subunit, is part of the DNA polymerase III holoenzyme. However, beta-clamp is not attached to polymerase III permanently like the other subunits. It is loaded on the DNA, by clamp loader, a subunit of DNA Pol III [ (PUBMED:27499105) ].

The beta clamp forms a ring shaped dimer that encircles dsDNA (sliding clamp) in bacteria. The bacterial beta clamp is a homodimer; each monomer consists of three globular domains to yield a six-domain ring [ (PUBMED:18191219) ]. It is structurally similar to the trimeric ring formed by proliferating cell nuclear antigen (PCNA) (found in eukaryotes and archaea) and the processivity factor (found in bacteriophages T4 and RB69) [ (PUBMED:1358275) ]. This structural correspondence further substantiates the mechanistic connection between eukaryotic and prokaryotic DNA replication that has been suggested on biochemical grounds.

GO process:DNA replication (GO:0006260)
GO component:DNA polymerase III complex (GO:0009360)
GO function:DNA binding (GO:0003677)
Family alignment:
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There are 21350 POL3Bc domains in 21350 proteins in SMART's nrdb database.

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