Ferp_0128 encodes a predicted archaeal nitrous-oxide reductase, EC 1.7.2.4. The protein belongs to the NosZ family and is predicted to catalyze nitrous oxide reduction to dinitrogen during anaerobic respiratory nitrogen oxide metabolism; literature directly maps Ferp_0128 to nosZ but does not provide purified-enzyme kinetics for the Ferroglobus protein.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004129 cytochrome-c oxidase activity | IEA GO_REF:0000002 | REMOVE | Summary: REMOVE. The specific assignment is nitrous-oxide reductase activity, not cytochrome-c oxidase activity. Reason: The InterPro cytochrome c oxidase subunit II-like domain reflects the copper-binding domain architecture shared with NosZ-like enzymes, but the protein-level assignment is nitrous-oxide reductase EC 1.7.2.4. The specific GO:0050304 annotation is present and should be used instead. Family research confirms that PTHR42838 mixes NosZ and cytochrome c oxidase subunit II-like CuA proteins, making this exact over-annotation risk predictable. Proposed replacements: nitrous-oxide reductase activity Supporting Evidence: file:FERPA/Ferp_0128/Ferp_0128-uniprot.txt RecName: Full=Nitrous-oxide reductase; EC=1.7.2.4. file:interpro/panther/PTHR42838/PTHR42838-deep-research-falcon.md PTHR42838 family research separates true NosZ/N2OR proteins from cytochrome c oxidase subunit II homologs, which share CuA-related sequence features but not catalytic function. |
| GO:0005507 copper ion binding | IEA GO_REF:0000002 | ACCEPT | Summary: ACCEPT. Nitrous-oxide reductase is a copper enzyme. Reason: NosZ enzymes are copper proteins, and the UniProt record annotates both copper binding and NosZ/cytochrome oxidase subunit II copper-binding domains for this sequence. Falcon supports a NosZ-family copper enzyme, but does not provide Ferp_0128-specific metal stoichiometry. Supporting Evidence: file:FERPA/Ferp_0128/Ferp_0128-uniprot.txt Cytochrome oxidase subunit II copper A binding. file:FERPA/Ferp_0128/Ferp_0128-deep-research-falcon.md NosZ enzymes are multicopper reductases with CuA/CuZ centers; direct Ferp_0128 metal loading or kinetic measurements were not recovered. |
| GO:0016020 membrane | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: KEEP_AS_NON_CORE. The enzyme is associated with respiratory envelope systems, but catalytic function and denitrification context are the core annotations. Reason: Membrane association is plausible for a respiratory nitrous-oxide reductase system, but this broad CC term is less informative than the enzyme activity and pathway annotations. The local evidence does not require making membrane the core feature of Ferp_0128. Falcon also found that F. placidus is an exception to common clade II NosZ Sec-signal patterns, so exact export/localization should not be inferred from clade alone. Supporting Evidence: file:FERPA/Ferp_0128/Ferp_0128-uniprot.txt GO; GO:0016020; C:membrane; IEA:InterPro. file:FERPA/Ferp_0128/Ferp_0128-deep-research-falcon.md Most clade II NosZ proteins have Sec-type signal motifs, but F. placidus was explicitly noted as an exception in the nosZ phylogeny. |
| GO:0050304 nitrous-oxide reductase activity | IEA GO_REF:0000003 | ACCEPT | Summary: ACCEPT. This is the specific molecular function expected for NosZ-like nitrous-oxide reductase. Reason: This is the precise EC-supported activity for the sequence. UniProt names the protein nitrous-oxide reductase, assigns EC 1.7.2.4, and places it in the NosZ family/PANTHER nitrous-oxide reductase subfamily. Falcon research found organism-specific literature explicitly referring to "nosZ; Ferp_0128", but the catalytic details are inferred from NosZ conservation rather than direct Ferp_0128 enzymology. Supporting Evidence: file:FERPA/Ferp_0128/Ferp_0128-uniprot.txt RecName: Full=Nitrous-oxide reductase; EC=1.7.2.4. file:FERPA/Ferp_0128/Ferp_0128-uniprot.txt PANTHER; PTHR42838:SF2; NITROUS-OXIDE REDUCTASE. file:interpro/panther/PTHR42838/PTHR42838-deep-research-falcon.md True NosZ/N2OR proteins catalyze N2O reduction to N2; cytochrome c oxidase subunit II homologs are distinct CuA-containing electron-entry proteins. file:FERPA/Ferp_0128/Ferp_0128-deep-research-falcon.md Smith et al. explicitly identify nitrous oxide reductase as nosZ; Ferp_0128 in F. placidus DSM 10642, while no direct purification or kinetic assay for Ferp_0128 was recovered. |
| GO:1902600 proton transmembrane transport | IEA GO_REF:0000108 | UNDECIDED | Summary: UNDECIDED. The protein is part of a respiratory process, but direct proton transmembrane transport by Ferp_0128 itself is not established by the local evidence. Reason: Nitrous-oxide reduction is coupled to anaerobic respiration at the pathway level, but Ferp_0128 is annotated as the terminal reductase enzyme, not as a proton pump. The local evidence does not justify direct proton transmembrane transport for this gene product. Supporting Evidence: file:FERPA/Ferp_0128/Ferp_0128-uniprot.txt Nitrous-oxide reductase is part of a bacterial respiratory chain that uses N2O as terminal electron acceptor. |
| GO:0019333 denitrification pathway | IEA GO_REF:0000041 | ACCEPT | Summary: ACCEPT. Ferp_0128 is a nitrous-oxide reductase, the terminal enzymatic step of denitrification, so UniPathway adds useful pathway context in an archaeal species. Reason: Unlike NorR regulatory examples, Ferp_0128 is predicted to catalyze the terminal denitrification reaction itself. The sequence belongs to the NosZ/nitrous-oxide reductase family and UniProt maps it to step 4/4 of nitrate reduction (denitrification). The strongest organism-specific evidence is locus identity and transcriptomic context, not an experiment demonstrating growth on N2O as terminal electron acceptor. Supporting Evidence: file:FERPA/Ferp_0128/Ferp_0128-uniprot.txt PATHWAY: Nitrogen metabolism; nitrate reduction (denitrification); dinitrogen from nitrate: step 4/4. file:FERPA/Ferp_0128/Ferp_0128-uniprot.txt Belongs to the NosZ family. file:interpro/panther/PTHR42838/PTHR42838-deep-research-falcon.md NosZ/N2OR is the terminal N2O-to-N2 enzyme of denitrification; clade and genome context affect ecology, but not the core reaction. file:FERPA/Ferp_0128/Ferp_0128-deep-research-falcon.md Ferp_0128/nosZ was not differentially regulated between Fe(III) oxide and Fe(III) citrate conditions in Smith et al.; nearby Ferp_0125 was up-regulated, so Fe(III)-oxide induction should not be assigned to nosZ. |
Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)