DnaB-DnaC-DnaT-PriA-PriB complex

GO:1990158 · Other · Nucleoprotein complex · Proposed

A protein-DNA complex consisting of the helicase loading complex DnaB-DnaC, replication restart proteins DnaT, PriA and PriB, and associated DNA. Involved in the restart of DNA replication after a stalled replication fork has been repaired. [GO:1990158]

Synonyms: DnaB-DnaC-DnaT-PriA-PriB preprimosome; phi-X174-type preprimosome

Has part: DnaB-DnaC complex (GO:1990100)

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Essential	Role
DnaB-DnaC complex	Protein complex	part of	`GO:1990100`		UNKNOWN	Helicase-loading subcomplex that donates DnaB during preprimosome assembly. `GO:1990158` GO:1990158 defines this preprimosome as containing the DnaB-DnaC helicase-loading complex. `PMID:8663104` Ng and Marians 1996 described ATP-dependent transfer of DnaB from DnaB-DnaC into a PriA-PriB-DnaT-PAS complex.
DnaT replication restart protein	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	dnaT	UNKNOWN	Replication-restart protein in the PriA-PriB-DnaT assembly intermediate. `GO:1990158` GO:1990158 defines DnaT as a constituent of this preprimosome. `PMID:8663104` Ng and Marians 1996 placed DnaT in the PriA-PriB-DnaT complex assembled at a PhiX174 primosome assembly site.
PriA replication restart protein	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	priA	UNKNOWN	Primosomal protein that recognizes primosome assembly site DNA. `GO:1990158` GO:1990158 defines PriA as a constituent of this preprimosome. `PMID:8663104` Ng and Marians 1996 described PriA recognition and binding at a PhiX174 primosome assembly site.
PriB replication restart protein	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	priB	UNKNOWN	Replication-restart protein that stabilizes the PriA-DNA complex. `GO:1990158` GO:1990158 defines PriB as a constituent of this preprimosome. `PMID:8663104` Ng and Marians 1996 reported that PriB stabilizes PriA on primosome assembly site DNA.
primosome assembly site DNA	Dna	part of			UNKNOWN	Single-stranded DNA scaffold carrying the primosome assembly site. `GO:1990158` GO:1990158 defines this preprimosome as a protein-DNA complex. `PMID:8663104` Ng and Marians 1996 assembled PriA-PriB-DnaT-DnaB protein-DNA complexes on PhiX174 primosome assembly site DNA.

Taxonomic distribution

NCBITaxon:562 Escherichia coli — COMMON: Ng and Marians 1996 reconstituted PhiX174-type primosome assembly with E. coli primosomal proteins. [PMID:8663104]

Canonical examples

NCBITaxon:562 Escherichia coli — Ng and Marians 1996 isolated PhiX174-type preprimosomal and primosomal protein-DNA complexes formed by E. coli PriA, PriB, PriC, DnaT, DnaB, DnaC and DnaG on single-stranded DNA. [PMID:8663105]

Functions

replication fork processing GO:0031297 — The DnaB-DnaC-DnaT-PriA-PriB preprimosome participates in restarting repaired stalled replication forks.
- GO:1990158 GO:1990158 defines this preprimosome by replication restart after a stalled replication fork has been repaired.
- GO:0031297 GO:0031297 is the Gene Ontology biological-process term for restoring and restarting a stalled DNA replication fork.
- PMID:8663105 Ng and Marians 1996 connected maintenance of the PhiX174-type primosome on replicated DNA with re-establishment of replication forks.

Mechanism graphs

DnaB-DnaC-DnaT-PriA-PriB supports fork restart (FUNCTION)

A DnaB-DnaC helicase-loading subcomplex and PriA, PriB and DnaT assemble on single-stranded primosome assembly site DNA to form a preprimosome used in replication restart.

Subject	Predicate	Object	Evidence
DnaB-DnaC complex	contributes to	DnaB-DnaC-DnaT-PriA-PriB complex	`GO:1990158` GO:1990158 includes the DnaB-DnaC helicase-loading complex.
PriA replication restart protein	contributes to	DnaB-DnaC-DnaT-PriA-PriB complex	`GO:1990158` GO:1990158 names PriA as a replication-restart constituent.
PriB replication restart protein	contributes to	DnaB-DnaC-DnaT-PriA-PriB complex	`GO:1990158` GO:1990158 names PriB as a replication-restart constituent.
DnaT replication restart protein	contributes to	DnaB-DnaC-DnaT-PriA-PriB complex	`GO:1990158` GO:1990158 names DnaT as a replication-restart constituent.
primosome assembly site DNA	scaffolds	DnaB-DnaC-DnaT-PriA-PriB complex	`GO:1990158` GO:1990158 defines this entity as a protein-DNA complex. `PMID:8663104` Ng and Marians 1996 assembled primosomal intermediates at a PhiX174 primosome assembly site.
DnaB-DnaC-DnaT-PriA-PriB complex	supports	replication fork processing	`GO:1990158` GO:1990158 defines this preprimosome by its involvement in replication restart after stalled replication fork repair. `GO:0031297` GO:0031297 defines replication fork processing as restoration and restart of a stalled replication fork.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral DnaT, PriA, PriB and primosome assembly site DNA groundings for the DnaB-DnaC-DnaT-PriA-PriB complex. GO:1990158 defines DnaT, PriA, PriB and associated DNA as constituents of this preprimosome. Exact source-neutral InterPro, Pfam, NCBIfam, UniProt family or SO sequence-feature CURIEs for these components need narrower curation before the labels can be grounded.
INTERPRETATION (RESOLVED): Leave PriC and DnaG out of the GO:1990158 DnaB-DnaC-DnaT-PriA-PriB complex. GO:1990158 denotes the PriA/PriB/DnaT/DnaB-DnaC preprimosome. GO models the PriC-containing alternative as separate sibling terms and models DnaG-containing entities as primosomes rather than pre-primosomes.

Evidence

GO:1990158 Gene Ontology cellular-component term for the DnaB-DnaC-DnaT-PriA-PriB complex and its PhiX174-type preprimosome synonymy.
GO:1990099 OLS reports GO:1990099 pre-primosome complex as the direct GO:1990158 is-a parent.
GO:1990100 Gene Ontology cellular-component term for the DnaB-DnaC helicase-loading subcomplex.
GO:0031297 Gene Ontology biological-process term for replication fork processing.
PMID:8663104 PubMed identifier for Ng and Marians 1996 part I, which analyzed ordered PhiX174-type primosome assembly intermediates.
DOI:10.1074/jbc.271.26.15642 DOI for Ng and Marians 1996, 'The ordered assembly of the phiX174-type primosome. I. Isolation and identification of intermediate protein-DNA complexes', as reported by PubMed.
PMID:8663105 PubMed identifier for Ng and Marians 1996 part II, the Journal of Biological Chemistry paper cited by GO:1990158.
DOI:10.1074/jbc.271.26.15649 DOI for Ng and Marians 1996, 'The ordered assembly of the phiX174-type primosome. II. Preservation of primosome composition from assembly through replication', as reported by PubMed.

Curation history

2026-10-01T04:44:54Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-10-01T04:46:44Z codex · EXPANDED_RECORD — Added GO synonymy, pre-primosome parentage, DnaB-DnaC subcomplex and DnaT/PriA/PriB/DNA components, E. coli/PhiX174 evidence, replication-fork-processing function evidence, GO/PubMed/DOI evidence, a nonmechanistic restart graph, and grounding/boundary discussions.
2026-10-01T05:03:44Z codex · FIX_VALIDATION — Replaced a bare components discussion anchor with explicit components#... anchors for the PriC/DnaG boundary discussion.
2026-10-01T05:16:35Z codex · FIX_REVIEW_ISSUE — #1855: typed the GO:1990100 DnaB-DnaC causal node as STRUCTURE.

Source: data/structures/other/dnab_dnac_dnat_pria_prib_complex.yaml