| Evidence source (paper, year, DOI URL) | What was studied (organism/protein) | Key findings on function/mechanism (reaction, metals, unusual residues) | Localization notes (e.g., signal peptide/secreted vs cytosolic/mitochondrial/peroxisomal prediction) | Quantitative/statistical data (gene counts, fold changes) | Implication for annotating A0A1D1VWP9 |
|---|---|---|---|---|---|
| Sim & Inoue, 2023, https://doi.org/10.1107/S2053230X2300523X | *Ramazzottius varieornatus* Cu/Zn SOD RvSOD15 (GenBank GAV02514.1) and modeled RvSOD family members | Authors treated RvSOD15 as a Cu/Zn SOD, refolded it with ZnSO4 and CuSO4, and solved crystal structures. However, RvSOD15 has an unusual Val87 substitution at a catalytic copper-ligand position; the V87H mutant still did not form a catalytically suitable copper site. Some RvSODs have deleted electrostatic loop/β3 sheet or unusual metal-binding residues, suggesting loss or reduction of canonical SOD activity rather than standard superoxide dismutation in all paralogs (pqac-00000000, pqac-00000001, pqac-00000002) | RvSOD15 was predicted to have an N-terminal signal peptide and thus be secreted; no direct localization data were provided for A0A1D1VWP9 or RvY_15948 (pqac-00000000) | Structural study; no accession-level statistics for A0A1D1VWP9. Qualitative family-level finding that some RvSODs may have low or lost SOD activity (pqac-00000001) | Strong evidence that *R. varieornatus* contains both canonical-looking and atypical Cu/Zn SOD-like proteins. Because A0A1D1VWP9 is only annotated as a Cu/Zn-binding-domain protein and was not directly studied, it should be annotated cautiously as a **SOD-like domain protein with probable metal-binding/oxidative-stress-related ancestry**, not assumed to be an active canonical SOD without sequence-level catalytic validation (pqac-00000000, pqac-00000001, pqac-00000002) |
| Sadowska-Bartosz & Bartosz, 2024, https://doi.org/10.3390/ijms25158393 | Review of antioxidant defenses in tardigrades, including *R. varieornatus* SOD repertoire | Reiterates canonical SOD function: SODs dismutate superoxide to O2 and H2O2. Reports both Cu/Zn and Mn SOD isoforms in tardigrades, but highlights that several *R. varieornatus* Cu/Zn SODs are structurally unusual and some may have lost canonical activity; therefore gene-family expansion alone does not prove enzymatic function for every paralog (pqac-00000003, pqac-00000004, pqac-00000015) | Review states predicted SOD localizations in *R. varieornatus* include mitochondria, cytosol, and peroxisomes; does not assign a specific compartment to A0A1D1VWP9 (pqac-00000003, pqac-00000008) | Reported SOD counts for tardigrades: *R. varieornatus* listed as 17 in a table, with text also mentioning 16; other counts: *E. sigismundi* 8, *R. coronifer* 14, *H. exemplaris* 15, *Homo sapiens* 3. CuZn-SODs are described as highly expressed in *R. varieornatus* (pqac-00000003, pqac-00000007, pqac-00000008) | Supports annotating A0A1D1VWP9 as part of a **large, diversified tardigrade SOD-like family** associated with oxidative-stress biology, but not necessarily as an active cytosolic Cu/Zn SOD enzyme. Family context favors oxidative defense relevance, while structural divergence argues for possible neofunctionalization or pseudocatalytic behavior (pqac-00000003, pqac-00000004, pqac-00000015) |
| Hashimoto et al., 2016, https://doi.org/10.1038/ncomms12808 | Genome of *Ramazzottius varieornatus* and stress-related gene repertoires | Reports genomic expansion of antioxidative enzymes, especially SODs, in *R. varieornatus*. This supports evolutionary selection on antioxidant capacity but does not provide direct biochemical proof for any one SOD paralog. The paper frames SOD expansion as a potential contributor to desiccation tolerance (pqac-00000009, pqac-00000011) | No accession-specific localization for A0A1D1VWP9 in the gathered snippet (pqac-00000009, pqac-00000011) | 16 SOD genes reported in the genome; authors also generated RNA-seq across six physiological states, though no direct A0A1D1VWP9 expression values were present in the snippet (pqac-00000009) | Supports a broad annotation that A0A1D1VWP9 belongs to an expanded antioxidant-enzyme family in *R. varieornatus*. However, genome context alone is insufficient to call it catalytically active; annotation should remain domain-based unless catalytic residues or activity are demonstrated (pqac-00000009, pqac-00000011) |
| Yoshida et al., 2017, https://doi.org/10.1371/journal.pbio.2002266 | Comparative genomics/transcriptomics of *R. varieornatus* vs *Hypsibius dujardini* | Reports that proteins related to protection from oxidants, including SOD and peroxiredoxin, were extensively duplicated in tardigrades. Also shows *R. varieornatus* has a much smaller inducible transcriptional response to desiccation than *H. dujardini*, consistent with constitutive readiness of stress-protection systems rather than strong induction alone (pqac-00000010, pqac-00000012, pqac-00000014) | No A0A1D1VWP9-specific localization in the gathered snippet (pqac-00000010, pqac-00000012) | Upregulated genes on anhydrobiosis entry: *R. varieornatus* 64 (0.5%) after fast desiccation and 307 (2.2%) after slow desiccation vs *H. dujardini* 1,422 (7.1%). Many stress-related genes in *R. varieornatus* were already highly expressed in active state (>100 TPM) (pqac-00000010, pqac-00000012, pqac-00000014) | Suggests A0A1D1VWP9 may function in a constitutively poised oxidative-stress network in active tardigrades. Still, this is pathway-level inference; it does not resolve whether the specific protein is an active Cu/Zn SOD, a secreted antioxidant, or a structurally derived SOD-like protein with altered function (pqac-00000010, pqac-00000012, pqac-00000014) |
| Giovannini et al., 2022, https://doi.org/10.3390/life12060817 | Antioxidant enzyme activities during anhydrobiosis in two eutardigrades (*Acutuncus antarcticus*, *Paramacrobiotus spatialis*) | Provides physiological context: SOD likely acts early in desiccation by converting superoxide into a less reactive molecule, with downstream peroxide detoxification by catalase. Responses differ across species, showing that SOD family members can be regulated differently during dehydration/rehydration (pqac-00000006) | No localization data for A0A1D1VWP9; no *R. varieornatus* protein-specific result (pqac-00000006) | Tardigrade SOD copy numbers summarized as ranging from 8 to 17 across species; in *A. antarcticus*, SOD activity reached the lowest value in desiccated animals (pqac-00000006) | Useful as functional background for superoxide-detoxifying SODs, but only indirect for A0A1D1VWP9. Supports the possibility that if A0A1D1VWP9 is catalytically active, its substrate would be superoxide and its pathway role would be ROS detoxification; however, no accession-specific evidence is provided (pqac-00000006) |
| Sadowska-Bartosz & Bartosz, 2024, https://doi.org/10.3390/ijms25158393 | Review of developmental/anhydrobiotic antioxidant regulation in tardigrades | Reports Cu/Zn SOD upregulation in early embryonic state and SOD upregulation in the tun state in some tardigrades, but species-specific behavior varies. This indicates that SOD family participation in oxidative-stress protection is biologically relevant even though not all family members are necessarily equivalent enzymes (pqac-00000005) | No accession-specific localization for A0A1D1VWP9 (pqac-00000005) | Examples include upregulation of SODs in tun state and >3-fold higher total glutathione in desiccated *P. richtersi*; a separate Mn-dependent peroxidase gene in *R. varieornatus* showed 2.5-fold induction, underscoring broader antioxidant remodeling (pqac-00000005) | Reinforces annotation of A0A1D1VWP9 within oxidative-stress/anhydrobiosis biology, but also shows that multiple antioxidant systems operate in parallel. For A0A1D1VWP9, the safest annotation remains **Cu/Zn SOD-like domain-containing protein, probable oxidative-stress-related protein; enzymatic activity and exact localization unresolved** (pqac-00000005) |


*Table: This table compiles the literature-based evidence most relevant to functional annotation of the Ramazzottius varieornatus Cu/Zn SOD-like protein A0A1D1VWP9 (RvY_15948). It distinguishes direct evidence from family-level inference and highlights why annotation should be cautious given the presence of atypical, potentially noncanonical SOD paralogs in tardigrades.*