PA4910 is a predicted nucleotide-binding (ATPase) subunit of an uncharacterised hydrophobic amino acid (HAAT family) ABC importer of Pseudomonas aeruginosa. It is a LivG-type ABC ATPase with a Walker A motif, an ABC_tran domain and the C-terminal BCA_ABC_TP_C extension, and it is encoded in a five-gene operon (PA4909-PA4913) that is a paralogue of the braCDEFG (LIV-I) branched-chain amino acid transport operon. As an ABC ATPase it associates with the cytoplasmic face of the inner membrane and couples ATP hydrolysis to transport by the operon's permease subunits (PA4911, PA4912). The substrate of this second system has not been determined biochemically; in a transposon-mutant growth screen the PA4910 mutant used D-alanine less well as a nitrogen source.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000166 nucleotide binding | IEA GO_REF:0000104 | TOO GENERAL | Summary: UniRule transfer of a generic nucleotide-binding function. Reason: True but uninformative; ATP binding (GO:0005524), which this review accepts below, is a descendant of it. Supporting Evidence: file:PSEAE/PA4910/PA4910-uniprot.txt PROSITE; PS00211; ABC_TRANSPORTER_1; 1. |
| GO:0005304 L-valine transmembrane transporter activity | IBA GO_REF:0000033 | UNDECIDED | Summary: PAINT IBA from PTN000656921 (the LivG ATPase node), seeded by E. coli LivG (P0A9S7). Reason: Substrate specificity in HAAT ABC importers is set by the periplasmic binding protein, not by the ATPase. PA4910 belongs to a second, uncharacterised system with its own binding protein (PA4913), whose substrates are unknown, and no L-valine phenotype was recorded for the PA4910 mutant in the only functional study. The valine claim is sound for E. coli LivG and for P. aeruginosa BraF (LIV-I), but cannot be assumed for this paralogue. Consistent with the treatment of the same IBA rows on PA4912. Propagation Review Root cause: UNRESOLVED Failure modes: SOURCE EVIDENCE WEAK Sources checked: PANTHER:PTN000656921 · PTN000656921 UNRESOLVED LivG ATPase node (25 leaves, 15 taxa) spanning several paralogous HAAT ATPases per genome (seven in Bradyrhizobium japonicum); the node cannot distinguish systems with different binding proteins. UniProtKB:P0A9S7 · E. coli LivG SUPPORTS SOURCE BUT NOT TARGET Sound for the E. coli LIV-I/LS systems; the target's own system has an undetermined substrate range. Supporting Evidence: PMID:18833300 PA4910 encodes a putative ATP-binding protein, while PA4912 encodes a predicted membrane component of this ABC amino acid transporter. |
| GO:0005524 ATP binding | IEA GO_REF:0000120 | ACCEPT | Summary: Combined IEA from the ABC transporter ATP-binding signatures. Reason: PA4910 carries the ABC_tran domain and both ABC transporter PROSITE signatures, including the Walker A/P-loop motif. Family and signature membership is good support for ATP binding. Supporting Evidence: file:PSEAE/PA4910/PA4910-uniprot.txt Pfam; PF00005; ABC_tran; 1. PMID:18833300 PA4910 encodes a putative ATP-binding protein, while PA4912 encodes a predicted membrane component of this ABC amino acid transporter. |
| GO:0005886 plasma membrane | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA from PTN002516950, seeded by an E. coli inner-membrane transport protein (P0A9V1). Reason: ABC importer ATPases have no transmembrane segments themselves but work bound to the cytoplasmic face of the permease subunits in the inner membrane, so is_active_in plasma membrane is the right claim. The paralogous BraF and BraG ATPases were recovered among membrane proteins. Supporting Evidence: PMID:18833300 Genes PA4910 and PA4912 comprise two genes of a five gene operon predicted to be involved in transport of branched chain amino acids. |
| GO:0015188 L-isoleucine transmembrane transporter activity | IBA GO_REF:0000033 | UNDECIDED | Summary: PAINT IBA from PTN000656921, seeded by E. coli LivG (P0A9S7). Reason: As for the L-valine row: the substrate range of this second HAAT system is unknown, and no isoleucine phenotype was recorded for PA4910. Consistent with PA4912. Propagation Review Root cause: UNRESOLVED Failure modes: SOURCE EVIDENCE WEAK Sources checked: PANTHER:PTN000656921 · PTN000656921 UNRESOLVED LivG ATPase node (25 leaves, 15 taxa) spanning several paralogous HAAT ATPases per genome; substrate specificity is set by each system's binding protein. UniProtKB:P0A9S7 · E. coli LivG SUPPORTS SOURCE BUT NOT TARGET Sound for the E. coli LIV-I/LS systems; the target's own system has an undetermined substrate range. Supporting Evidence: PMID:18833300 PA4910 encodes a putative ATP-binding protein, while PA4912 encodes a predicted membrane component of this ABC amino acid transporter. |
| GO:0015192 L-phenylalanine transmembrane transporter activity | IBA GO_REF:0000033 | MARK AS OVER ANNOTATED | Summary: PAINT IBA from PTN000656921, seeded by E. coli LivG (P0A9S7). Reason: The phenylalanine function of E. coli LivG depends on the E. coli binding-protein repertoire (LivJ and LivK). P. aeruginosa LIV-I has the single BraC binding protein, characterised as Leu/Ile/Val plus Ala/Thr with no report of Phe, and PA4910's own system has an uncharacterised binding protein. Consistent with braF, braD and PA4912. Propagation Review Root cause: PROPAGATION BAD Failure modes: FUNCTIONAL DIVERGENCE Sources checked: UniProtKB:P0A9S7 · E. coli LivG SUPPORTS SOURCE BUT NOT TARGET The phenylalanine specificity comes from the E. coli binding proteins, not from the ATPase lineage. Supporting Evidence: PMID:18833300 PA4910 encodes a putative ATP-binding protein, while PA4912 encodes a predicted membrane component of this ABC amino acid transporter. |
| GO:0015808 L-alanine transport | IBA GO_REF:0000033 | UNDECIDED | Summary: PAINT IBA from PTN000656921, seeded by P. aeruginosa BraF (P21629, the LIV-I ATPase). Reason: L-alanine is an established secondary substrate of LIV-I (BraCDEFG), so the claim is sound for BraF, but PA4910 is the ATPase of a different system and showed no L-alanine phenotype in the growth screen (only D-alanine). Consistent with the UNDECIDED treatment of this row on PA4912. Propagation Review Root cause: UNRESOLVED Failure modes: SOURCE EVIDENCE WEAK Sources checked: PANTHER:PTN000656921 · PTN000656921 UNRESOLVED LivG ATPase node (25 leaves, 15 taxa); a substrate-level term propagates poorly where each system has its own binding protein. UniProtKB:P21629 · braF (PA1071) SUPPORTS SOURCE BUT NOT TARGET Sound for the LIV-I ATPase, whose substrates are established; PA4910 belongs to a different, uncharacterised system. Supporting Evidence: PMID:18833300 Disruption of PA4910 resulted in reduced utilization of D-Alanine (as a nitrogen source), while PA4912 mutants had disrupted D-Alanine and D-Valine utilization (Table 2). |
| GO:0015823 phenylalanine transport | IEA GO_REF:0000108 | MARK AS OVER ANNOTATED | Summary: Automatic process annotation derived from the L-phenylalanine transporter activity row above. Reason: Inherits the problem of its source row: the phenylalanine specificity is an E. coli binding-protein property. Consistent with braF and PA4912. Supporting Evidence: PMID:18833300 PA4910 encodes a putative ATP-binding protein, while PA4912 encodes a predicted membrane component of this ABC amino acid transporter. |
| GO:0016887 ATP hydrolysis activity | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro2GO mapping from the ABC transporter ATP-binding domain. Reason: The ABC_tran domain is the ATP-hydrolysing engine of ABC transporters, with both PROSITE ABC signatures present; this is the activity the subunit contributes to its transporter. Supporting Evidence: file:PSEAE/PA4910/PA4910-uniprot.txt Pfam; PF00005; ABC_tran; 1. |
| GO:0042941 D-alanine transmembrane transport | IBA GO_REF:0000033 | UNDECIDED | Summary: PAINT IBA from PTN000656921, seeded by BraF (P21629) and by PA4910 itself, both resting on partial D-alanine growth defects in one Biolog screen. Reason: PA4910 in its own WITH/FROM is expected for a seed. No D-alanine uptake or binding has been shown for either system, and both seeds are the same kind of partial nutrient-utilisation phenotype from the same screen. A D-amino acid importer is a plausible reading of the PA4910 and PA4912 phenotypes, but it is not established. Consistent with braF, braD and PA4912. Propagation Review Root cause: UNRESOLVED Failure modes: SOURCE EVIDENCE WEAK Sources checked: PANTHER:PTN000656921 · PTN000656921 UNRESOLVED LivG ATPase node (25 leaves, 15 taxa); substrate specificity is set by each system's binding protein, so a substrate-level term propagates poorly here. UniProtKB:P21629 · braF (PA1071) SOURCE WEAK OR INFERRED PseudoCAP growth-screen IMP for the LIV-I ATPase; a different system from PA4910's. UniProtKB:Q9HUQ3 · PA4910 (self; IBD seed, IMP PMID:18833300) SOURCE WEAK OR INFERRED Partial D-alanine nitrogen-source growth defect; no uptake assay. Supporting Evidence: PMID:18833300 Disruption of PA4910 resulted in reduced utilization of D-Alanine (as a nitrogen source), while PA4912 mutants had disrupted D-Alanine and D-Valine utilization (Table 2). |
| GO:0042941 D-alanine transmembrane transport | IMP PMID:18833300 High-throughput phenotypic characterization of Pseudomonas a... | UNDECIDED | Summary: PseudoCAP IMP seed for PTN000656921. The PA4910 transposon mutant grows less well on D-alanine as a nitrogen source. Reason: Seed verdict INDIRECT-PHENOTYPE. The phenotype is real but partial, from one Biolog screen, with no uptake or binding assay, and the operon's binding protein has not been characterised. It is the only functional data on this system, so the row is neither accepted nor rejected. Consistent with PA4912 and the bra genes. Supporting Evidence: PMID:18833300 Disruption of PA4910 resulted in reduced utilization of D-Alanine (as a nitrogen source), while PA4912 mutants had disrupted D-Alanine and D-Valine utilization (Table 2). |
| GO:1903714 isoleucine transmembrane transport | IEA GO_REF:0000117 | UNDECIDED | Summary: ARBA prediction of isoleucine transport. Reason: Same substrate question as the isoleucine transporter activity IBA: this system's substrates are unknown and the prediction rests on an association rule, not on evidence for this protein. Supporting Evidence: PMID:18833300 Genes PA4910 and PA4912 comprise two genes of a five gene operon predicted to be involved in transport of branched chain amino acids. |
| GO:1903785 L-valine transmembrane transport | IEA GO_REF:0000117 | UNDECIDED | Summary: ARBA prediction of L-valine transport. Reason: Same substrate question as the L-valine transporter activity IBA. Supporting Evidence: PMID:18833300 Genes PA4910 and PA4912 comprise two genes of a five gene operon predicted to be involved in transport of branched chain amino acids. |
| GO:1903805 L-valine import across plasma membrane | IBA GO_REF:0000033 | UNDECIDED | Summary: PAINT IBA from PTN000656921, seeded by BraF (P21629, PseudoCAP IMP from the same growth screen). Reason: Sound for BraF, whose system transports valine (uptake in cells, BraC binding, proteoliposome reconstitution), but PA4910's system has an uncharacterised binding protein and no valine phenotype. Consistent with PA4912. Propagation Review Root cause: UNRESOLVED Failure modes: SOURCE EVIDENCE WEAK Sources checked: PANTHER:PTN000656921 · PTN000656921 UNRESOLVED LivG ATPase node (25 leaves, 15 taxa); a substrate-level term propagates poorly where each system has its own binding protein. UniProtKB:P21629 · braF (PA1071) SUPPORTS SOURCE BUT NOT TARGET Sound for the LIV-I ATPase, whose substrates are established; PA4910 belongs to a different, uncharacterised system. Supporting Evidence: PMID:18833300 Genes PA4910 and PA4912 comprise two genes of a five gene operon predicted to be involved in transport of branched chain amino acids. |
| GO:1903806 L-isoleucine import across plasma membrane | IBA GO_REF:0000033 | UNDECIDED | Summary: PAINT IBA from PTN000656921, seeded by BraF (P21629). Reason: Sound for BraF (LIV-I carries isoleucine), not established for this paralogous system. Consistent with PA4912. Propagation Review Root cause: UNRESOLVED Failure modes: SOURCE EVIDENCE WEAK Sources checked: PANTHER:PTN000656921 · PTN000656921 UNRESOLVED LivG ATPase node (25 leaves, 15 taxa); a substrate-level term propagates poorly where each system has its own binding protein. UniProtKB:P21629 · braF (PA1071) SUPPORTS SOURCE BUT NOT TARGET Sound for the LIV-I ATPase, whose substrates are established; PA4910 belongs to a different, uncharacterised system. Supporting Evidence: PMID:18833300 Genes PA4910 and PA4912 comprise two genes of a five gene operon predicted to be involved in transport of branched chain amino acids. |
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Download this section (compressed HTML)Q: Does the PA4913 periplasmic binding protein bind D-amino acids, and does the PA4909-PA4913 system import them?
Experiment: Measure binding of D-alanine, D-valine and the branched-chain L-amino acids to purified PA4913 by intrinsic fluorescence or ITC, and measure radiolabelled D-alanine uptake in a PA4909-PA4913 deletion strain with and without complementation.
What is not known — curated, literature-grounded statements of the open unknowns (the inverse of core functions).
Gap: The substrate range of the PA4909-PA4913 ABC importer is undetermined. No uptake or binding measurement exists for any amino acid, so it is unknown whether the system carries D-amino acids, branched-chain L-amino acids, or something else.
BIOLOGY
What is known: Established: the operon encodes a complete HAAT-type ABC importer paralogous to braCDEFG, and transposon mutants of PA4910 and PA4912 use D-alanine (and, for PA4912, D-valine) less well as nitrogen sources.
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