recG

UniProt ID: Q88C73
Organism: Pseudomonas putida (strain ATCC 47054 / DSM 6125 / CFBP 8728 / NCIMB 11950 / KT2440)
Review Status: DRAFT
Aliases:
PP_5310
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Gene Description

RecG is an ATP-dependent 3-prime-to-5-prime DNA helicase and branch-migration translocase that remodels branched DNA intermediates during recombination, DNA repair, and stalled-replication-fork processing. It provides a route for Holliday-junction branch migration that is mechanistically parallel to RuvAB, and can regress blocked replication forks into four-way structures.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0000166 nucleotide binding
IEA
GO_REF:0000104 		MARK AS OVER ANNOTATED
Summary: Correct but uninformative relative to ATP binding and hydrolysis.
Reason: More specific nucleotide-dependent activities are already annotated.
GO:0003676 nucleic acid binding
IEA
GO_REF:0000002 		MARK AS OVER ANNOTATED
Summary: Correct at a broad level but does not capture RecG's directional DNA-translocase activity.
Reason: GO:0043138 provides the relevant substrate and directionality.
GO:0003678 DNA helicase activity
IEA
GO_REF:0000120 		MARK AS OVER ANNOTATED
Summary: Correct parent term but redundant with the exact 3-prime-to-5-prime activity.
Reason: GO:0043138 is the more informative existing annotation.
GO:0005524 ATP binding
IEA
GO_REF:0000120 		KEEP AS NON CORE
Summary: ATP binding is required for RecG catalysis but is subordinate to ATP hydrolysis and directional helicase activity.
Reason: The binding term is valid but does not independently summarize the biological mechanism.
GO:0006281 DNA repair
IEA
GO_REF:0000120 		ACCEPT
Summary: RecG remodels branched repair and stalled-fork intermediates.
Reason: DNA repair is a conserved central process for RecG-family helicases.
Supporting Evidence:
file:PSEPK/recG/recG-uniprot.txt
Plays a critical role in recombination and DNA repair.
PMID:18375550
independent pathways that branch migrate Holliday junctions during recombinational DNA repair
GO:0006310 DNA recombination
IEA
GO_REF:0000120 		ACCEPT
Summary: RecG catalyzes branch migration of recombination intermediates.
Reason: This process follows directly from the conserved RecG mechanism.
Supporting Evidence:
file:PSEPK/recG/recG-uniprot.txt
process Holliday junction intermediates to mature products by
GO:0016787 hydrolase activity
IEA
GO_REF:0000104 		MARK AS OVER ANNOTATED
Summary: Correct parent term but too broad relative to ATP hydrolysis.
Reason: GO:0016887 captures the actual hydrolysis substrate.
GO:0016887 ATP hydrolysis activity
IEA
GO_REF:0000120 		ACCEPT
Summary: RecG hydrolyzes ATP to power DNA translocation and branch migration.
Reason: The conserved helicase domains and Rhea reaction support this catalytic activity.
GO:0043138 3'-5' DNA helicase activity
IEA
GO_REF:0000120 		ACCEPT
Summary: RecG couples ATP hydrolysis to DNA unwinding and branch migration with 3-prime-to-5-prime polarity.
Reason: This is the exact directional motor activity of the RecG subfamily.

Core Functions

Uses ATP hydrolysis to translocate on DNA and branch-migrate Holliday junctions or regress stalled replication forks.

Molecular Function:
3'-5' DNA helicase activity
Directly Involved In:
DNA recombination DNA repair
Supporting Evidence:
  • file:PSEPK/recG/recG-uniprot.txt
    Has a DNA unwinding activity characteristic of a DNA helicase
  • file:PSEPK/recG/recG-uniprot.txt
    translocating in the 3'-5' direction.
  • PMID:18375550
    RecG also has been shown to directly convert stalled replication forks into Holliday junctions.

References

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Suggested Questions for Experts

Q: How much does RecG contribute to junction migration relative to RuvAB in KT2440?

Suggested Experiments

Experiment: Compare recombination and fork-restart phenotypes of recG, ruvB, and recG-ruvB mutants under defined DNA damage.

Type: genetic pathway validation

📚 Additional Documentation

Notes

(recG-notes.md)

recG curation notes

  • Q88C73 is a RecG-family ATP-dependent 3-prime-to-5-prime helicase that branch-migrates Holliday junctions and regresses stalled forks [UniProtKB:Q88C73, "Has a DNA unwinding activity characteristic of a DNA helicase with 3'-5' polarity"].
  • RecG is modeled as a route parallel to RuvAB rather than as a RuvABC subunit or resolvase. Comparative work supports independent RecG and RuvABC branch-migration pathways [PMID:18375550, "they participate in independent pathways that branch migrate Holliday junctions during recombinational DNA repair"].
  • The same study shows that RecG products and repair outcomes are taxon-dependent when a compatible resolver is absent [PMID:18375550, "deployment of the RecG pathway is lethal"]. The module therefore leaves the RecG-to-RuvC handoff unverified in KT2440.

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