DadA1 (PA5304; also called DadA) is the FAD-dependent D-amino acid dehydrogenase of Pseudomonas aeruginosa PAO1, encoded in the dadAX operon with the alanine racemase DadX and controlled by the Lrp-family regulator DadR, which responds to L-alanine. The purified recombinant enzyme alone oxidatively deaminates a very broad range of D-amino acids (all tested except D-glutamate and D-glutamine) to the corresponding 2-oxo acids, with similar kcat and Km on D-alanine, D-histidine, D-phenylalanine and others. A dadA1 mutant cannot use L-alanine, D-alanine and a set of other D-amino acids as nitrogen source, placing DadA1 at the centre of alanine and D-amino acid catabolism; with DadX it converts L-alanine via D-alanine to pyruvate. By homology to E. coli DadA it is a membrane-associated enzyme that passes electrons to the respiratory chain.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005737 cytoplasm | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: IBA cytoplasm from the deep DAO-family node PTN000354057. Reason: DadA1 has no signal peptide and is expected at the cytoplasmic face of the inner membrane; plausible but untested, and not where the activity is specifically known to act. Supporting Evidence: file:PSEAE/dadA1/dadA1-uniprot.txt Belongs to the DadA oxidoreductase family. |
| GO:0005886 plasma membrane | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: IBA plasma membrane from the E. coli DadA seed (P0A6J5). Reason: E. coli DadA is membrane-associated; DadA1 is in the same HAMAP family. Reasonable inheritance, untested for the P. aeruginosa enzyme. Supporting Evidence: file:PSEAE/dadA1/dadA1-uniprot.txt HAMAP; MF_01202; DadA; 1. |
| GO:0008718 D-amino-acid dehydrogenase activity | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from PTN008552203 (DadA clade; 3 seeds, 10 leaf IBAs in 8 taxa). Seeds are E. coli DadA (P0A6J5, IDA), DadA1 itself (PseudoCAP IDA, PMID:21378189) and DadA2 (Q9HU99; PseudoCAP IDA to PMID:17021207, a wrong reference recorded on the dadA2 review). Reason: The node term suits a DadA clade and the IBD stands on the E. coli DadA and DadA1 seeds. DadA1 appearing among its own sources reflects its own experimental annotation. Supporting Evidence: PMID:21378189 purified recombinant DadA alone was sufficient to demonstrate the proposed enzymatic activity with very broad substrate specificity |
| GO:0008718 D-amino-acid dehydrogenase activity | IDA PMID:21378189 Regulation and characterization of the dadRAX locus for D-am... | ACCEPT | Summary: PseudoCAP IDA, a PTN008552203 seed row. Purified recombinant DadA1 oxidises nearly all D-amino acids tested. Reason: The abstract states directly that purified recombinant DadA has the D-amino acid dehydrogenase activity, with kinetic constants for several substrates; UniProt ties the kinetics to PA5304. Seed verdict SOUND. Supporting Evidence: PMID:21378189 purified recombinant DadA alone was sufficient to demonstrate the proposed enzymatic activity with very broad substrate specificity file:PSEAE/dadA1/dadA1-uniprot.txt Catalyzes the oxidative deamination of D-amino acids. Has very broad substrate specificity; all the D-amino acids tested can be used as the substrate except D-Glu and D-Gln. |
| GO:0008718 D-amino-acid dehydrogenase activity | IEA GO_REF:0000120 | ACCEPT | Summary: UniRule/InterPro DadA family mapping. Reason: Agrees with the direct biochemical evidence. Supporting Evidence: file:PSEAE/dadA1/dadA1-uniprot.txt HAMAP; MF_01202; DadA; 1. |
| GO:0019478 D-amino acid catabolic process | IEA GO_REF:0000120 | ACCEPT | Summary: UniRule/InterPro mapping to D-amino acid catabolic process. Reason: DadA1 is required for use of D-alanine, D-histidine, D-phenylalanine, D-serine, D-threonine and D-valine as nitrogen source; the general term captures this broad role, alongside the more specific D-alanine catabolic process. Supporting Evidence: file:PSEAE/dadA1/dadA1-uniprot.txt Participates in the utilization of several D-amino acids as the sole source of nitrogen, i.e. D-alanine, D-histidine, D-phenylalanine, D-serine, D-threonine, and D-valine. |
| GO:0055130 D-alanine catabolic process | IBA GO_REF:0000033 | ACCEPT | Summary: IBA D-alanine catabolic process from the E. coli DadA seed. Reason: The dadA1 mutant cannot use D-alanine (or L-alanine, via DadX) as nitrogen source, and DadA1 oxidises D-alanine to pyruvate in vitro. Supporting Evidence: file:PSEAE/dadA1/dadA1-uniprot.txt Cells lacking this gene lose the ability to utilize D-alanine, D-histidine, D-phenylalanine, D-serine, D-threonine, and D-valine as the sole source of nitrogen. |
| GO:0055130 D-alanine catabolic process | IEA GO_REF:0000041 | ACCEPT | Summary: UniPathway mapping (D-alanine degradation). Reason: Consistent with the mutant and enzyme data. Supporting Evidence: file:PSEAE/dadA1/dadA1-uniprot.txt Cells lacking this gene lose the ability to utilize D-alanine, D-histidine, D-phenylalanine, D-serine, D-threonine, and D-valine as the sole source of nitrogen. |
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Experiment: Fractionate PAO1 grown on alanine and assay DadA1 activity in membrane and soluble fractions with artificial and quinone acceptors.
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