POL3Bc DNA polymerase III beta subunit
SMART ACC:	SM000480
Description:	-
InterPro ACC:	IPR001001
InterPro abstract:	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 … expand 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. collapse
GO process:	DNA replication (GO:0006260)
GO component:	DNA polymerase III complex (GO:0009360)
GO function:	DNA binding (GO:0003677)
Family alignment:	View the Family alignment or the Alignment consensus sequence
There are 21 350 POL3Bc domains in 21 350 proteins in SMART's NRDB database.

Taxonomic distribution of proteins containing POL3Bc domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing POL3Bc domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Predicted cellular role

Cellular role:	Replication

Relevant references for this domain

Primary literature for the POL3Bc domain is listed below. Automatically-derived, secondary literature is also available.

KEGG pathways involving proteins which contain this domain

This information is based on the mapping of SMART genomic protein database to KEGG orthologous groups. Percentages are related to the number of proteins containing a POL3Bc domain which could be assigned to a KEGG orthologous group, and not all proteins containing POL3Bc domains. Please note that proteins can be included in multiple pathways, ie. the numbers below will not add to 100%.

KEGG pathways

KEGG orthologous groups

Some of these KOs are included in the interactive Pathways Explorer overview maps. Select an overview map and click the button below to highlight them in iPath.

3D structures in PDB containing this domain

Links to other resources describing this domain

Pfam	DNA_pol3_beta
InterPro	IPR001001