| Entity | Evidence type | Key finding | Quantitative details | Source (paper + year + URL) | Citation context ID |
|---|---|---|---|---|---|
| RvSOD15 (Ramazzottius varieornatus strain YOKOZUNA-1) | Crystal structure | Cu/Zn-containing SOD-like enzyme; catalyzes the canonical Cu/Zn SOD reaction in the family context: dismutation of superoxide to O2 and H2O2; copper and zinc were confirmed at expected sites, supporting Cu/Zn-SOD family assignment | Reaction given as 2O2•− + 2H+ -> O2 + H2O2; anomalous scattering confirmed Cu/Zn; structure solved at 2.2 A | Sim & Inoue 2023, Acta Crystallogr F, https://doi.org/10.1107/S2053230X2300523X | (pqac-00000008, pqac-00000009) |
| RvSOD15 | Crystal structure | Active site is highly unusual for a Cu/Zn SOD: one histidine ligand of the catalytic copper center is replaced by Val87, implying likely impairment of canonical SOD catalysis | Val87 replaces the histidine found at the equivalent catalytic Cu-binding position in typical Cu/Zn SODs; 44% similarity to human SOD1 and 56% to H. exemplaris putative CuZnSOD | Sim & Inoue 2023, Acta Crystallogr F, https://doi.org/10.1107/S2053230X2300523X | (pqac-00000008, pqac-00000009) |
| RvSOD15 | Crystal structure | Overall fold remains Cu/Zn-SOD-like: Greek-key beta-barrel with electrostatic loop and metal-binding loop; forms a eukaryotic-like dimer | Monomer has 8 antiparallel beta strands; 6 monomers in crystal, 4 forming dimers in asymmetric unit and others by symmetry; wild-type PDB 7ypp | Sim & Inoue 2023, Acta Crystallogr F, https://doi.org/10.1107/S2053230X2300523X | (pqac-00000009, pqac-00000007, pqac-00000011) |
| RvSOD15 | Crystal structure | Zn site is close to canonical Cu/Zn SODs, but the catalytic Cu site is distorted; Cu is coordinated by only 3 histidines in T-shaped geometry with 2 weakly interacting waters, consistent with reduced activity | WatA/WatB at 2.6-3.4 A from Cu; protein ligands comprise only 3 histidines; wild-type copper geometry T-shaped | Sim & Inoue 2023, Acta Crystallogr F, https://doi.org/10.1107/S2053230X2300523X | (pqac-00000002, pqac-00000007, pqac-00000011) |
| RvSOD15 V87H mutant | Crystal structure / mutational inference | Restoring His at position 87 does not fully rescue a catalytic copper site because a flexible loop destabilizes His87 coordination; supports very low or lost SOD activity | Only 3 of 6 molecules show His87 coordination; His87-Cu distances are unusually long at 2.7-2.8 A versus typical approximately 2.03 A | Sim & Inoue 2023, Acta Crystallogr F, https://doi.org/10.1107/S2053230X2300523X | (pqac-00000002, pqac-00000007, pqac-00000011) |
| RvSOD15 | Crystal structure / localization prediction | Predicted to be secreted based on an N-terminal signal peptide, so likely functions outside the cytosol if expressed as annotated | N-terminal signal peptide predicted; no direct localization experiment reported | Sim & Inoue 2023, Acta Crystallogr F, https://doi.org/10.1107/S2053230X2300523X | (pqac-00000003, pqac-00000010) |
| RvSOD15 | Crystal structure / functional inference | Electrostatic and metal-binding loops are altered relative to canonical Cu/Zn SODs, giving a less charged substrate-guiding surface and a more disordered metal-binding region; these features may depress activity | Metal-binding loop has 2-residue insertion after Cys96; loop lacks helical structure seen in other CuZnSODs; Tyr97 adopts alternative conformations | Sim & Inoue 2023, Acta Crystallogr F, https://doi.org/10.1107/S2053230X2300523X | (pqac-00000002, pqac-00000007) |
| R. varieornatus CuZn-SOD paralogs | Genome/transcriptome + structural modeling | The species has an expanded SOD repertoire, but several paralogs are atypical (truncated proteins, mutated ligand residues, deleted loops), suggesting diversification and possible neofunctionalization or loss of classical SOD activity | Review summarizes 17 SOD genes in R. varieornatus (vs 3 in humans); structural classes include alpha, beta, gamma, delta, epsilon; beta/gamma include mutated metal sites or missing electrostatic loop/beta3 sheet | Sadowska-Bartosz & Bartosz 2024, Int J Mol Sci, https://doi.org/10.3390/ijms25158393; Sim & Inoue 2023, https://doi.org/10.1107/S2053230X2300523X | (pqac-00000004, pqac-00000005, pqac-00000013, pqac-00000014, pqac-00000001) |
| R. varieornatus CuZn-SOD paralogs | Genome/transcriptome | Antioxidant genes, including SOD family members, are constitutively abundant and/or induced under slow desiccation; R. varieornatus shows more limited transcriptional change than H. dujardini, implying preparedness rather than strong inducibility | SOD duplicated in both tardigrade species compared; genes induced by slow desiccation included antioxidant-related genes; no gene-specific fold change for RvY_10893-1 reported | Yoshida et al. 2017, PLOS Biology, https://doi.org/10.1371/journal.pbio.2002266 | (pqac-00000015) |
| R. varieornatus SOD family | Genome/review | High constitutive antioxidant capacity is part of tardigrade stress biology; CuZn-SODs are described as highly expressed in R. varieornatus, though paralog-specific values are not given | 16-17 SODs reported for R. varieornatus depending on source/table interpretation; probable localization across mitochondria, cytosol, and peroxisomes | Sadowska-Bartosz & Bartosz 2024, Int J Mol Sci, https://doi.org/10.3390/ijms25158393 | (pqac-00000005, pqac-00000013) |
| General Cu/Zn SOD1 | Review / canonical family framework | Canonical Cu/Zn SODs are homodimeric beta-barrel metalloenzymes that bind Cu and Zn and dismutate superoxide radicals; this is the baseline for annotating R. varieornatus homologs | Reaction: 2O2•− + 2H+ -> H2O2 + O2; typical Cu/Zn SOD1 forms homodimer; each monomer is a beta-barrel plus loops | Liu et al. 2025, Antioxidants, https://doi.org/10.3390/antiox14070809 | (pqac-00000006) |
| General Cu/Zn SOD1 vs A0A1D1VE88 mapping | Annotation inference | UniProt A0A1D1VE88 (gene RvY_10893-1) is annotated as a Cu/Zn superoxide dismutase, but the retrieved literature directly characterizes RvSOD15 and broader paralog sets rather than explicitly mapping A0A1D1VE88 to RvSOD15; therefore, functional annotation for A0A1D1VE88 should rely primarily on UniProt family/domain assignment plus indirect species-level evidence | UniProt-provided domains match Cu/Zn SOD family; literature directly names nearby paralogs such as RvSOD12 (RvY_10892.1), RvSOD14 (RvY_10894.1), and RvSOD15, but no explicit paper-based mapping of A0A1D1VE88/RvY_10893-1 to RvSOD15 was found | Sim & Inoue 2023, Acta Crystallogr F, https://doi.org/10.1107/S2053230X2300523X; Sadowska-Bartosz & Bartosz 2024, https://doi.org/10.3390/ijms25158393 | (pqac-00000009, pqac-00000004) |


*Table: This table summarizes the strongest evidence relevant to functional annotation of Ramazzottius varieornatus Cu/Zn superoxide dismutases, emphasizing the structurally characterized RvSOD15 and how far current literature can be mapped to UniProt A0A1D1VE88 (RvY_10893-1). It is useful for distinguishing direct experimental findings from family-level inference and for flagging the current mapping uncertainty for the specific target accession.*