RecG (PA5345) is the ATP-dependent DNA helicase of Pseudomonas aeruginosa that processes branched DNA: by homology with E. coli RecG it drives Holliday-junction branch migration and regresses stalled replication forks, translocating with 3'-5' polarity, and so acts in recombinational DNA repair. In P. aeruginosa recG forms an operon with oxyR; recG mutants are hypersensitive to UV, mitomycin C, chromate, tellurite and selenite and less resistant to peroxides. RecG has also been reported to bind palindromic promoter regions of OxyR-controlled genes and to promote their induction, possibly by unwinding these sequences.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000166 nucleotide binding | IEA GO_REF:0000104 | TOO GENERAL | Summary: UniRule keyword mapping. Reason: GO:0005524 ATP binding, kept in this review, is_a GO:0000166. Supporting Evidence: file:PSEAE/recG/recG-uniprot.txt IPR014001; Helicase_ATP-bd |
| GO:0003676 nucleic acid binding | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO mapping from the DEAD/DEAH helicase domain. Reason: Correct but general; RecG acts on branched DNA (Holliday junctions and forks), so GO:0000400 four-way junction DNA binding is the supported specific term. Proposed replacements: four-way junction DNA binding Supporting Evidence: file:PSEAE/recG/recG-uniprot.txt Helps process Holliday junction intermediates to mature products by catalyzing branch migration. |
| GO:0003678 DNA helicase activity | IBA GO_REF:0000033 | TOO GENERAL | Summary: IBA from the PTN002773745 IBD (4 seeds: E. coli, M. tuberculosis and B. subtilis RecG, and PA5345 itself). The IBD stands on the characterised RecG orthologs without this gene's seed. Reason: True; GO:0009378 four-way junction helicase activity and GO:0043138 3'-5' DNA helicase activity, both accepted in this review, are is_a descendants of GO:0003678. Supporting Evidence: file:PSEAE/recG/recG-uniprot.txt Has a DNA unwinding activity characteristic of a DNA helicase with 3'-5' polarity. |
| GO:0003678 DNA helicase activity | IDA PMID:22621928 ATP-dependent RecG helicase is required for the transcriptio... | TOO GENERAL | Summary: PseudoCAP IDA and one of the four seeds of the PTN002773745 GO:0003678 IBD. Purified RecG unwound palindromic promoter DNA in an ATP-dependent way. Seed verdict UNVERIFIABLE (organism of the purified protein not stated in the abstract), term correct. Reason: Helicase activity is certainly correct for RecG, but the more specific GO:0009378 and GO:0043138, accepted in this review, entail it. No defect filed: nothing in the abstract positively indicates that the protein assayed was not PA5345. Supporting Evidence: PMID:22621928 The OxyR tetramer preferentially binds to promoters after RecG has generated linear DNA in the presence of ATP |
| GO:0003678 DNA helicase activity | IEA GO_REF:0000002 | TOO GENERAL | Summary: InterPro2GO mapping from the RecG family signature. Reason: GO:0009378 and GO:0043138, accepted in this review, are is_a descendants of GO:0003678. Supporting Evidence: file:PSEAE/recG/recG-uniprot.txt IPR004609; ATP-dep_DNA_helicase_RecG |
| GO:0005524 ATP binding | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: InterPro/UniRule mapping from the helicase ATP-binding domain. Reason: True for an ATP-dependent helicase; a ligand-binding facet of the helicase activity. Supporting Evidence: file:PSEAE/recG/recG-uniprot.txt IPR014001; Helicase_ATP-bd |
| GO:0006281 DNA repair | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from the PTN002773745 GO:0006281 IBD (2 seeds: PA5345 and Arabidopsis RECG1, which has its own TAIR IMP for DNA repair). PA5345 being a seed is expected, not circular. Reason: Core BP; RecG is a DNA repair helicase and the IBD stands on RECG1 as well. Supporting Evidence: PMID:10913087 The recG ::Gm mutant was hypersensitive to UV and was killed by more than 5 log units within 20 s of irradiation. |
| GO:0006281 DNA repair | IEA GO_REF:0000120 | ACCEPT | Summary: InterPro/UniRule mapping. Reason: Consistent with the experimental rows. Supporting Evidence: file:PSEAE/recG/recG-uniprot.txt Plays a critical role in recombination and DNA repair. |
| GO:0006281 DNA repair | IMP PMID:10913087 Role of the Pseudomonas aeruginosa oxyR-recG operon in oxida... | ACCEPT | Summary: PseudoCAP IMP and a seed of the PTN002773745 GO:0006281 IBD. A recG::Gm mutant is UV hypersensitive and partially complemented in trans. Seed verdict SOUND. Reason: RecG is itself a DNA repair helicase, so the UV sensitivity reflects loss of its own repair function rather than an indirect effect. Supporting Evidence: PMID:10913087 The recG ::Gm mutant was hypersensitive to UV and was killed by more than 5 log units within 20 s of irradiation. PMID:10913087 Expression of the recG gene in trans partially restored UV tolerance in the recG ::Gm mutant. |
| GO:0006281 DNA repair | IMP PMID:16105671 Involvement of DNA helicases in chromate resistance by Pseud... | ACCEPT | Summary: PseudoCAP IMP and a seed of the same IBD. The recG mutant is sensitive to chromate and mitomycin C, rescued by the wild-type gene. Seed verdict SOUND. Reason: Sensitivity to DNA-damaging agents with complementation, for a known repair helicase. Supporting Evidence: PMID:16105671 both mutant strains showed an increased susceptibility to the toxic oxyanions tellurite and selenite as well as to mitomycin C, but not to arsenite, paraquat and hydrogen peroxide. |
| GO:0006310 DNA recombination | IEA GO_REF:0000120 | ACCEPT | Summary: InterPro/UniRule mapping. Reason: RecG catalyses Holliday-junction branch migration, a step of homologous recombination. Supporting Evidence: file:PSEAE/recG/recG-uniprot.txt Helps process Holliday junction intermediates to mature products by catalyzing branch migration. |
| GO:0009378 four-way junction helicase activity | IDA PMID:22621928 ATP-dependent RecG helicase is required for the transcriptio... | ACCEPT | Summary: PseudoCAP IDA from the Yeom et al. paper (purified RecG unwinding palindromic, potentially cruciform-forming, promoter DNA). Reason: Four-way junction (Holliday junction) branch migration is the defining activity of the RecG family, as stated by UniRule. The abstract does not show a junction substrate or the organism of the purified protein, but the curator read the full text and the function is clearly correct for the gene, so the row is accepted in deference. Supporting Evidence: file:PSEAE/recG/recG-uniprot.txt Helps process Holliday junction intermediates to mature products by catalyzing branch migration. PMID:22621928 The OxyR tetramer preferentially binds to promoters after RecG has generated linear DNA in the presence of ATP |
| GO:0016787 hydrolase activity | IEA GO_REF:0000104 | TOO GENERAL | Summary: UniRule keyword mapping. Reason: GO:0016887 ATP hydrolysis activity, kept in this review, is_a GO:0016787. Supporting Evidence: file:PSEAE/recG/recG-uniprot.txt IPR014001; Helicase_ATP-bd |
| GO:0016887 ATP hydrolysis activity | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: Rhea/ARBA mapping from the ATPase reaction. Reason: ATP hydrolysis drives the helicase; true but a component of the helicase activity rather than an independent function. Supporting Evidence: file:PSEAE/recG/recG-uniprot.txt Couples ATP hydrolysis with the unwinding of duplex DNA by translocating in the 3'-5' direction. |
| GO:0034599 cellular response to oxidative stress | IMP PMID:10913087 Role of the Pseudomonas aeruginosa oxyR-recG operon in oxida... | KEEP AS NON CORE | Summary: PseudoCAP IMP; the recG mutant was less resistant to H2O2 and cumene hydroperoxide in disk assays. Reason: Supported by the full text, but likely a consequence of the DNA repair defect (oxidative DNA damage). A second paper found no H2O2 sensitivity in a recG transposon mutant, so the phenotype is modest. Non-core. Supporting Evidence: PMID:10913087 Still, recG appeared to be essential for optimal resistance to H 2 O 2 and CHP, and the recG mutant could be complemented by the recG gene in trans . PMID:16105671 both mutant strains showed an increased susceptibility to the toxic oxyanions tellurite and selenite as well as to mitomycin C, but not to arsenite, paraquat and hydrogen peroxide. |
| GO:0034644 cellular response to UV | IMP PMID:10913087 Role of the Pseudomonas aeruginosa oxyR-recG operon in oxida... | KEEP AS NON CORE | Summary: PseudoCAP IMP; UV hypersensitivity of the recG mutant. Reason: True; the UV response is the repair of UV-induced DNA damage, captured by GO:0006281. Supporting Evidence: PMID:10913087 The recG ::Gm mutant was hypersensitive to UV and was killed by more than 5 log units within 20 s of irradiation. |
| GO:0043138 3'-5' DNA helicase activity | IEA GO_REF:0000120 | ACCEPT | Summary: EC 5.6.2.4 mapping. Reason: RecG translocates 3'-5' on DNA, as stated by UniRule and shown for E. coli RecG. Supporting Evidence: file:PSEAE/recG/recG-uniprot.txt Has a DNA unwinding activity characteristic of a DNA helicase with 3'-5' polarity. |
| GO:0071247 cellular response to chromate | IMP PMID:16105671 Involvement of DNA helicases in chromate resistance by Pseud... | KEEP AS NON CORE | Summary: PseudoCAP IMP; chromate hypersensitivity of the recG mutant, complemented. Reason: True; reflects repair of chromate-induced DNA damage. Non-core. Supporting Evidence: PMID:16105671 The chromate resistance phenotype in mutants GGP-64 and AJ-22 was restored by cosmids bearing wild type ruvB or recG genes, respectively. |
| GO:0072715 cellular response to selenite ion | IMP PMID:16105671 Involvement of DNA helicases in chromate resistance by Pseud... | KEEP AS NON CORE | Summary: PseudoCAP IMP; selenite sensitivity of the recG mutant. Reason: True as a mutant sensitivity, likely through DNA damage. Non-core. Supporting Evidence: PMID:16105671 both mutant strains showed an increased susceptibility to the toxic oxyanions tellurite and selenite as well as to mitomycin C, but not to arsenite, paraquat and hydrogen peroxide. |
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Download this section (compressed HTML)Q: Is the reported promoter-unwinding role of RecG in OxyR regulon induction a direct transcriptional function, or an indirect effect of its DNA repair and replication roles?
Experiment: Purify P. aeruginosa PA5345 and assay branch migration on synthetic Holliday junctions and forks, alongside the palindromic katB/ahpB promoter fragments used by Yeom et al.; test OxyR-regulon induction in a recG point mutant lacking ATPase activity.
Type: biochemistry and genetics
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