| Entity (gene/protein) | Evidence type | Key finding | Biological implication | Source (paper + year + URL) |
|---|---|---|---|---|
| **RvY_03757.1 (RvSOD6 variant 3)** | Structural / sequence analysis | Explicitly identified in *Ramazzottius varieornatus* as **RvSOD6 variant 3 (RvY_03757.1)** and reported to be **truncated**; grouped among atypical Cu/Zn SOD-like genes that are nevertheless expressed in transcriptome data. (pqac-00000000, pqac-00000007, pqac-00000008) | Supports assignment of **A0A1D1UP59** to the RvSOD family, but the truncation argues that its **canonical Cu/Zn superoxide dismutase activity is uncertain** or potentially reduced/lost; no direct localization or biochemical assay was reported for this specific protein in the provided literature. (pqac-00000000, pqac-00000007) | Sim & Inoue 2023, *Acta Crystallographica Section F* — https://doi.org/10.1107/S2053230X2300523X |
| **RvSOD15 (GenBank GAV02514.1)** | Structural | Crystal structures of wild-type and V87H mutant were solved; protein is a **Cu/Zn-containing SOD-like protein** with experimentally confirmed Cu and Zn binding, but it has an unusual **Val87 substitution** at a canonical copper-ligand position and a flexible/disordered metal-binding loop. (pqac-00000001, pqac-00000002, pqac-00000003) | Direct evidence that at least one *R. varieornatus* RvSOD family member binds Cu/Zn. However, the unusual active-site architecture suggests some duplicated tardigrade Cu/Zn SODs may have **non-canonical or diminished SOD function**. (pqac-00000001, pqac-00000003) | Sim & Inoue 2023, *Acta Crystallographica Section F* — https://doi.org/10.1107/S2053230X2300523X |
| **RvSOD15 (GenBank GAV02514.1)** | Structural / localization inference | Predicted to contain an **N-terminal signal peptide**, indicating that this protein is **secreted**. (pqac-00000002, pqac-00000007) | Shows that not all tardigrade Cu/Zn SOD-like proteins are necessarily cytosolic; some family members likely function in the **extracellular/secretory compartment**. (pqac-00000002, pqac-00000007) | Sim & Inoue 2023, *Acta Crystallographica Section F* — https://doi.org/10.1107/S2053230X2300523X |
| **Cu/Zn SOD gene family in *R. varieornatus*** | Transcriptomic | Comparative transcriptomics reported **16 putative CuZn-SOD genes** in *R. cf. varieornatus* with cumulative expression **1533.6840 TPM**. (pqac-00000004) | Indicates a **large and actively expressed Cu/Zn SOD repertoire**, consistent with strong antioxidant capacity and likely importance in oxidative-stress management in tardigrades. (pqac-00000004) | Kamilari et al. 2019, *BMC Genomics* — https://doi.org/10.1186/s12864-019-5912-x |
| **SOD gene family in *R. varieornatus*** | Review | Review summarizes *R. varieornatus* as having **17 SOD genes**, exceeding the typical metazoan complement (noted as usually fewer than 10; humans have 3). (pqac-00000005) | Supports the view that antioxidant-gene expansion is a notable genomic feature of *R. varieornatus*, though expansion alone may not guarantee canonical enzymatic function for every paralog. (pqac-00000005) | Sadowska-Bartosz & Bartosz 2024, *International Journal of Molecular Sciences* — https://doi.org/10.3390/ijms25158393 |
| **Atypical RvSOD paralogs in *R. varieornatus*** | Structural / review synthesis | Several RvSOD genes besides RvY_03757.1 are described as atypical: some are **truncated**, while others harbor **numerous mutations in copper-binding residues**; the review highlights that some RvSODs may have evolved to **lose SOD function**. (pqac-00000000, pqac-00000005, pqac-00000007) | Functional annotation of any single RvSOD paralog, including **RvY_03757**, should therefore be treated cautiously: family membership supports a Cu/Zn SOD-like assignment, but **direct biochemical confirmation is lacking** for many paralogs. (pqac-00000000, pqac-00000005, pqac-00000007) | Sim & Inoue 2023, *Acta Crystallographica Section F* — https://doi.org/10.1107/S2053230X2300523X; Sadowska-Bartosz & Bartosz 2024, *Int J Mol Sci* — https://doi.org/10.3390/ijms25158393 |
| **SOD repertoire in tardigrades / *R. varieornatus*** | Review | Review states tardigrade SODs are likely distributed across **mitochondria, cytosol, and peroxisomes**, and frames SOD expansion as part of antioxidant defenses associated with survival under hostile conditions and recovery from cryptobiosis. (pqac-00000006) | For **RvY_03757/A0A1D1UP59**, localization is **not directly demonstrated**; compartment assignment remains inferential from family-level tardigrade biology rather than gene-specific evidence. (pqac-00000006, pqac-00000007) | Sadowska-Bartosz & Bartosz 2024, *International Journal of Molecular Sciences* — https://doi.org/10.3390/ijms25158393 |


*Table: This table summarizes the evidence available for the Ramazzottius varieornatus Cu/Zn SOD-like gene RvY_03757 and the broader RvSOD family. It distinguishes direct gene-specific findings from family-level inferences, which is critical because several tardigrade SOD paralogs appear atypical or truncated.*