DnaB helicase complex

GO:1990161 · Other · Multiprotein complex · Proposed

A homohexameric protein complex that possesses DNA helicase activity; functions during DNA replication and repair. [GO:1990161]

Synonyms: DnaB hexamer

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
DnaB helicase	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	dnaB	6 copies per DnaB helicase hexamer	UNKNOWN	Protein subunit that homohexamerizes to form the replicative DnaB helicase ring. `GO:1990161` GO:1990161 defines the DnaB helicase complex as homohexameric. `PMID:17947583` Bailey, Eliason and Steitz 2007 solved crystal structures of the hexameric DnaB helicase. `PDB:2R6D` RCSB PDB entry 2R6D contains six chains of Geobacillus stearothermophilus replicative DNA helicase DnaB.

NCBITaxon:1422 Geobacillus stearothermophilus — COMMON: PDB 2R6D is a hexameric DnaB helicase crystal form from Geobacillus stearothermophilus. [PDB:2R6D]

NCBITaxon:1422 Geobacillus stearothermophilus — Bailey, Eliason and Steitz 2007 solved Geobacillus stearothermophilus DnaB hexamer crystal forms, including PDB 2R6D. [PMID:17947583]

DNA helicase activity GO:0003678 — The DnaB helicase complex unwinds a DNA helix using ATP hydrolysis.
- GO:1990161 GO:1990161 defines the DnaB helicase complex as possessing DNA helicase activity.
- GO:0003678 GO:0003678 is the Gene Ontology molecular function term for ATP-dependent DNA helix unwinding.
- PMID:17947583 Bailey, Eliason and Steitz 2007 studied the DnaB helicase ring that unwinds duplex DNA at the eubacterial replication fork.

Six DnaB subunits form a helicase ring that unwinds DNA at the eubacterial replication fork.

Subject	Predicate	Object	Evidence
DnaB helicase	contributes to	DnaB helicase complex	`GO:1990161` GO:1990161 defines the DnaB helicase complex as homohexameric.
DnaB helicase complex	supports	DNA helicase activity	`GO:1990161` GO:1990161 defines the complex by DNA helicase activity. `GO:0003678` GO:0003678 defines DNA helicase activity as ATP-dependent DNA helix unwinding.

CURATION_TODO (OPEN): Resolve an exact source-neutral DnaB family grounding for the DnaB helicase complex. GO:1990161 defines the DnaB helicase complex as a homohexameric DnaB assembly. An exact source-neutral InterPro, Pfam, NCBIfam or UniProt family CURIE for the monomeric DnaB component needs narrower curation before the label can be grounded.

GO:1990161 Gene Ontology cellular-component term for the DnaB helicase complex and its DnaB hexamer synonym.
GO:0033202 OLS reports GO:0033202 DNA helicase complex as the direct GO:1990161 is-a parent.
GO:0003678 Gene Ontology molecular-function term for DNA helicase activity.
PMID:17947583 PubMed identifier for Bailey, Eliason and Steitz 2007, the Science paper cited by GO:1990161.
DOI:10.1126/science.1147353 DOI for Bailey, Eliason and Steitz 2007, 'Structure of hexameric DnaB helicase and its complex with a domain of DnaG primase', as reported by PubMed.
PDB:2R6D RCSB PDB entry for a Geobacillus stearothermophilus hexameric DnaB crystal form from Bailey, Eliason and Steitz 2007.

2026-10-01T04:15:45Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-10-01T04:16:35Z codex · EXPANDED_RECORD — Added GO synonymy and DNA-helicase-complex parentage, a DnaB reviewed-label-only component, Geobacillus/PDB scope, DNA helicase activity evidence, GO/PubMed/DOI/PDB evidence, a nonmechanistic helicase-activity graph, and a grounding discussion.