Aliphatic sulfonates import ATP-binding protein SsuB2 (VPARA_09230, A0A0H2MBB8) in Variovorax paradoxus strain TBEA6 is a 276-amino-acid peripheral inner-membrane ATPase subunit (InterPro IPR003439, PANTHER PTHR42788:SF17) of the SsuABC ATP-binding cassette (ABC) importer complex. Encoded on genomic contig JZWI01000005 (EMBL KLN57912.1) at the 5' end of the aliphatic sulfonate uptake and desulfonation gene cluster immediately upstream of the transmembrane permease ssuC5 (VPARA_09240, KLN57913.1) and the alkanesulfonate monooxygenase ssuD (VPARA_09250, KLN57914.1), and clustered with the periplasmic binding protein ssuA2 (VPARA_09270, KLN57916.1) and the FMN reductase ssuE (VPARA_09290, KLN57918.1), SsuB2 contains a conserved ABC nucleotide-binding domain (PROSITE PS50893, Pfam PF00005, residues 19-240) with a canonical Walker A P-loop ATP-binding motif at residues 51-58 (51-GRSGCGKS-58) that hydrolyzes ATP to energize transmembrane import of aliphatic sulfonates across the cytoplasmic membrane.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000166 nucleotide binding | IEA GO_REF:0000104 | TOO GENERAL | Summary: True but uninformative parent molecular function already entailed by the accepted specific child term GO:0005524 (ATP binding). Reason: GO:0000166 (nucleotide binding) is a broad ancestor term that adds no specificity beyond GO:0005524 (ATP binding) already accepted in this review. Supporting Evidence: file:VARPD/ssuB2/ssuB2-uniprot.txt FT BINDING 51..58 FT /ligand="ATP" FT /ligand_id="ChEBI:CHEBI:30616" FT /evidence="ECO:0000256|PROSITE-ProRule:PRU00434" |
| GO:0005524 ATP binding | IEA GO_REF:0000120 | ACCEPT | Summary: Core nucleotide-binding activity of the ABC transporter catalytic domain (PROSITE PS50893, residues 19-240) anchored by the Walker A motif at residues 51-58 (51-GRSGCGKS-58). Reason: SsuB2 contains a canonical ABC transporter nucleotide-binding domain (PROSITE PS50893, InterPro IPR003439, residues 19-240) with a conserved Walker A P-loop ATP-binding site at residues 51-58 (51-GRSGCGKS-58, PROSITE-ProRule PRU00434). Supporting Evidence: file:VARPD/ssuB2/ssuB2-uniprot.txt FT BINDING 51..58 FT /ligand="ATP" FT /ligand_id="ChEBI:CHEBI:30616" FT /evidence="ECO:0000256|PROSITE-ProRule:PRU00434" |
| GO:0016887 ATP hydrolysis activity | IEA GO_REF:0000002 | ACCEPT | Summary: Core intrinsic catalytic activity of the SsuB2 ATP-binding cassette subunit, which hydrolyzes ATP to power conformational cycling of the SsuC5 transmembrane permease. Reason: As the nucleotide-binding and hydrolyzing subunit of the SsuABC importer (PROSITE PS50893, InterPro IPR003439, PANTHER PTHR42788:SF17), SsuB2 catalyzes ATP hydrolysis to drive active import of aliphatic sulfonates across the inner membrane (matching the treatment in PSEPK/ssuB). Supporting Evidence: file:VARPD/ssuB2/ssuB2-uniprot.txt FT DOMAIN 19..240 FT /note="ABC transporter" FT /evidence="ECO:0000259|PROSITE:PS50893" PMID:10781557 The first group consists of ssuA , ssuB , and ssuC , which are the genes for a putative ATP-binding cassette (ABC)-type transport system. |
| GO:0042918 alkanesulfonate transmembrane transport | IC PMID:10781557 The ssu locus plays a key role in organosulfur metabolism in... | NEW | Summary: Core biological process energized by SsuB2 as the ATPase subunit of the SsuA2B2C5 alkanesulfonate importer. Reason: Inferred by curator (IC) because SsuB2 belongs to PANTHER PTHR42788:SF17 (ALIPHATIC SULFONATES IMPORT ATP-BINDING PROTEIN SSUB) and is encoded on contig JZWI01000005 (KLN57912.1) immediately upstream of the permease ssuC5 (VPARA_09240, KLN57913.1) and the monooxygenase ssuD (VPARA_09250, KLN57914.1) and clustered with ssuA2 (VPARA_09270, KLN57916.1) and ssuE (VPARA_09290, KLN57918.1) to drive alkanesulfonate transmembrane transport (GO:0042918; PMID:10781534, PMID:10781557). Supporting Evidence: file:VARPD/ssuB2/ssuB2-uniprot.txt DR PANTHER; PTHR42788:SF17; ALIPHATIC SULFONATES IMPORT ATP-BINDING PROTEIN SSUB; 1. PMID:10781557 The first group consists of ssuA , ssuB , and ssuC , which are the genes for a putative ATP-binding cassette (ABC)-type transport system. |
| GO:0005886 plasma membrane | IC PMID:10781557 The ssu locus plays a key role in organosulfur metabolism in... | NEW | Summary: Peripheral inner-membrane localization at the cytoplasmic face of the SsuC5 transmembrane permease. Reason: Inferred by curator (IC) because SsuB2 is the ABC ATP-binding subunit (PROSITE PS50893, PANTHER PTHR42788:SF17) that assembles with the integral inner-membrane permease SsuC5 (VPARA_09240) at the cytoplasmic face of the bacterial plasma membrane (GO:0005886; PMID:10781557). Supporting Evidence: file:VARPD/ssuB2/ssuB2-uniprot.txt FT DOMAIN 19..240 FT /note="ABC transporter" FT /evidence="ECO:0000259|PROSITE:PS50893" PMID:10781557 The first group consists of ssuA , ssuB , and ssuC , which are the genes for a putative ATP-binding cassette (ABC)-type transport system. |
| GO:0055052 ATP-binding cassette (ABC) transporter complex, substrate-binding subunit-containing | IC PMID:10781557 The ssu locus plays a key role in organosulfur metabolism in... | NEW | Summary: ATP-hydrolyzing subunit of the tripartite SsuA2-SsuB2-SsuC5 ABC alkanesulfonate importer complex. Reason: Inferred by curator (IC) because SsuB2 (VPARA_09230, KLN57912.1) is encoded immediately upstream of the transmembrane permease ssuC5 (VPARA_09240, UniProtKB:A0A0H2M6G6, KLN57913.1) and clustered with the periplasmic binding protein ssuA2 (VPARA_09270, UniProtKB:A0A0H2M784, KLN57916.1) on contig JZWI01000005, forming the ATPase subunit of the substrate-binding-subunit-containing SsuABC importer complex (GO:0055052; PMID:10781534, PMID:10781557). Supporting Evidence: file:VARPD/ssuB2/ssuB2-uniprot.txt DR EMBL; JZWI01000005; KLN57912.1; -; Genomic_DNA. PMID:10781557 The first group consists of ssuA , ssuB , and ssuC , which are the genes for a putative ATP-binding cassette (ABC)-type transport system. |
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Download this section (compressed HTML)Q: Is SsuB2 (VPARA_09230) strictly dedicated to the co-localized SsuA2-SsuC5 translocon in Variovorax paradoxus TBEA6, or can it also energize any of the paralogous SsuC permeases encoded elsewhere in the TBEA6 genome?
Suggested experts: Kertesz MA, Leisinger T
Experiment: Construct a clean in-frame ΞssuB2 (VPARA_09230) deletion in Variovorax paradoxus TBEA6 and measure growth on C2-C8 linear alkanesulfonates and sulfonated buffers (HEPES, MOPS) as sole sulfur sources.
Hypothesis: Deletion of ssuB2 impairs growth on alkanesulfonates imported via the VPARA_09230-VPARA_09290 ssu cluster while leaving taurine utilization via TauAB1C intact.
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