ureC1 encodes the urease alpha catalytic subunit NVIE_014740 in Nitrososphaera viennensis EN76. It hydrolyzes imported urea intracellularly, supplying ammonia/ammonium for nitrogen metabolism and ammonia oxidation when urea is available.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0009039 urease activity | IEA GO_REF:0000120 | ACCEPT | Summary: ACCEPT. UreC is the catalytic alpha subunit of urease, EC 3.5.1.5. Reason: The UniProt record names ureC1 as urease subunit alpha and assigns EC 3.5.1.5. NCBIfam TIGR01792 and PANTHER PTHR43440 support conserved urease alpha-subunit function. Falcon research also found organism-specific literature mapping NVIE_014740 to the regulated EN76 urease locus. Supporting Evidence: file:9ARCH/ureC1/ureC1-uniprot.txt RecName: Full=Urease subunit alpha; EC=3.5.1.5. file:9ARCH/ureC1/ureC1-uniprot.txt NCBIfam; TIGR01792; urease_alph; 1. file:9ARCH/ureC1/ureC1-deep-research-falcon.md Recent EN76 literature explicitly identifies ureC/NVIE_014740 as the urease alpha subunit in a urea transporter-urease operon. |
| GO:0016151 nickel cation binding | IEA GO_REF:0000120 | ACCEPT | Summary: ACCEPT. Urease is a nickel metalloenzyme, so nickel binding is expected. Reason: Nickel binding is part of the urease catalytic mechanism. The UniProt record explicitly states that the enzyme binds two nickel ions per subunit. Family research notes that rare iron ureases exist, so nickel binding should be supported by gene-specific evidence rather than propagated blindly from urease-family membership. Supporting Evidence: file:9ARCH/ureC1/ureC1-uniprot.txt Binds 2 nickel ions per subunit. file:interpro/panther/PTHR43440/PTHR43440-deep-research-falcon.md PTHR43440 family research supports nickel-dependent urease annotations for canonical UreC homologs with explicit Ni-binding evidence, while warning that iron urease paralogs make blanket nickel propagation unsafe. |
| GO:0016787 hydrolase activity | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: KEEP_AS_NON_CORE. Correct but less informative than urease activity. Reason: Urease is a hydrolase, but this parent term is less informative than GO:0009039 urease activity and should not be treated as the core MF. Supporting Evidence: file:9ARCH/ureC1/ureC1-uniprot.txt RecName: Full=Urease subunit alpha; EC=3.5.1.5. |
| GO:0016810 hydrolase activity, acting on carbon-nitrogen (but not peptide) bonds | IEA GO_REF:0000002 | KEEP AS NON CORE | Summary: KEEP_AS_NON_CORE. Correct parent activity for urease, but the specific urease activity is the core molecular function. Reason: This parent C-N hydrolase term is technically consistent with urease chemistry, but GO:0009039 is the supported specific activity. Supporting Evidence: file:9ARCH/ureC1/ureC1-uniprot.txt RecName: Full=Urease subunit alpha; EC=3.5.1.5. |
| GO:0019627 urea metabolic process | IEA GO_REF:0000104 | ACCEPT | Summary: ACCEPT. Urease directly metabolizes urea. Reason: ureC1 encodes the catalytic urease subunit, so urea metabolic process is a direct biological-process annotation, not merely pathway context. In EN76, urea utilization is regulated by nitrogen source and ureC/ut transcripts respond to urea versus ammonia. Supporting Evidence: file:9ARCH/ureC1/ureC1-uniprot.txt PATHWAY: Nitrogen metabolism; urea degradation; CO(2) and NH(3) from urea (urease route): step 1/1. file:interpro/panther/PTHR43440/PTHR43440-deep-research-falcon.md Family research identifies canonical UreC/large-subunit ureases as the catalytic subunits for urea hydrolysis, supporting urea catabolism for conserved UreC proteins. file:9ARCH/ureC1/ureC1-deep-research-falcon.md In N. viennensis EN76, ut and ureC/NVIE_014740 transcripts change about tenfold after urea versus ammonia addition, supporting regulated urea utilization by this locus. |
| GO:0043419 urea catabolic process | IEA GO_REF:0000041 | ACCEPT | Summary: ACCEPT. The UniPathway annotation is specific and useful for this nitrogen-metabolism gene: ureC1 is a urease catalytic subunit that directly catalyzes urea degradation. Reason: UniPathway adds the correct process for the catalytic reaction. Urease hydrolyzes urea to ammonium and hydrogencarbonate/CO2, making urea catabolism direct rather than regulatory or downstream context. The Falcon report further supports intracellular urea hydrolysis rather than an extracellular urease model for EN76. Supporting Evidence: file:9ARCH/ureC1/ureC1-uniprot.txt PATHWAY: Nitrogen metabolism; urea degradation; CO(2) and NH(3) from urea (urease route): step 1/1. file:9ARCH/ureC1/ureC1-deep-research-falcon.md Culture studies found no extracellular urease activity and no secretion signal context for the urease genes, supporting intracellular urea catabolism in ammonia-oxidizing archaea including EN76. |
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