NrdA (PA1156) is the 963-residue large (alpha, R1) subunit of the aerobic class Ia ribonucleotide reductase (RNR) of Pseudomonas aeruginosa PAO1, one of the three RNR classes (Ia, II and III) the organism encodes. NrdA carries the catalytic site that reduces ribonucleoside diphosphates to 2'-deoxyribonucleoside diphosphates, the allosteric specificity site, and an atypical duplicated N-terminal ATP-cone. Only the first ATP-cone is allosterically functional, binding ATP or dATP to regulate overall activity. NrdA forms an exceptionally tight complex with the radical-generating NrdB (beta, R2) subunit, suggested to be alpha4beta4, and so supplies deoxyribonucleotides for DNA synthesis.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000166 nucleotide binding | IEA GO_REF:0000104 | TOO GENERAL | Summary: UniRule nucleotide binding. Reason: True, but GO:0005524 ATP binding, accepted in this review for the allosteric ATP-cone, is an is_a descendant of nucleotide binding. Supporting Evidence: PMID:16829681 an allosteric domain that can bind either ATP or dATP and regulates the overall enzyme activity |
| GO:0004748 ribonucleoside-diphosphate reductase activity, thioredoxin disulfide as acceptor | IBA GO_REF:0000033 | ACCEPT | Summary: IBA RNR activity from PTN000171388 (class I R1 subunits). Reason: NrdA is the catalytic subunit of a class Ia RNR; the abstract states it harbours the active site, and the wild-type enzyme was characterised in vitro. Supporting Evidence: PMID:16829681 The RNR of this study (class Ia) is a complex of the NrdA protein harboring the active site and the allosteric sites and the NrdB protein harboring a tyrosyl radical necessary to initiate catalysis. |
| GO:0004748 ribonucleoside-diphosphate reductase activity, thioredoxin disulfide as acceptor | IEA GO_REF:0000120 | ACCEPT | Summary: Combined IEA RNR activity (IPR013509, RHEA:23252, EC 1.17.4.1). Reason: Consistent with the biochemistry. Supporting Evidence: PMID:16829681 The RNR of this study (class Ia) is a complex of the NrdA protein harboring the active site and the allosteric sites |
| GO:0005524 ATP binding | IBA GO_REF:0000033 | ACCEPT | Summary: IBA ATP binding from PTN000171388. Reason: ATP binds the allosteric ATP-cone (activity site) and the specificity site of class Ia R1 subunits; the abstract states the N-terminal ATP-cone of P. aeruginosa NrdA is functional. Supporting Evidence: PMID:16829681 The N-terminal ATP-cone (ATP-c1) is allosterically functional, whereas the internal ATP-cone lacks allosteric activity. |
| GO:0005524 ATP binding | IEA GO_REF:0000120 | ACCEPT | Summary: Combined IEA ATP binding. Reason: As for the IBA row. Supporting Evidence: PMID:16829681 an allosteric domain that can bind either ATP or dATP and regulates the overall enzyme activity |
| GO:0005971 ribonucleoside-diphosphate reductase complex | IBA GO_REF:0000033 | ACCEPT | Summary: IBA RNR complex from PTN000171388; NrdA is one of nine seeds. Reason: Sound; NrdA's own IDA is among the seeds as expected, and the NrdA-NrdB complex was characterised directly. Supporting Evidence: PMID:16829681 The P. aeruginosa wild type NrdA and NrdB proteins form an extraordinarily tight complex with a suggested alpha4beta4 composition. |
| GO:0005971 ribonucleoside-diphosphate reductase complex | IDA PMID:16829681 Ribonucleotide reductase modularity: Atypical duplication of... | ACCEPT | Summary: PseudoCAP IDA RNR complex; a seed of the PTN000171388 complex IBD. Reason: The abstract states directly that purified NrdA and NrdB form a tight complex of suggested alpha4beta4 composition. Supporting Evidence: PMID:16829681 The P. aeruginosa wild type NrdA and NrdB proteins form an extraordinarily tight complex with a suggested alpha4beta4 composition. |
| GO:0009263 deoxyribonucleotide biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: IBA deoxyribonucleotide biosynthesis from PTN000171388. Reason: RNR performs the committed step of de novo deoxyribonucleotide synthesis. Supporting Evidence: PMID:16829681 The RNR enzymes are central for de novo synthesis of deoxyribonucleotides and essential to all living cells. |
| GO:0009263 deoxyribonucleotide biosynthetic process | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro2GO deoxyribonucleotide biosynthesis (IPR013509). Reason: As for the IBA row. Supporting Evidence: PMID:16829681 The RNR enzymes are central for de novo synthesis of deoxyribonucleotides and essential to all living cells. |
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Download this section (compressed HTML)Q: Does the second, allosterically inactive ATP-cone of P. aeruginosa NrdA have a structural role in stabilising the alpha4beta4 complex?
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