| Property | Details/Description |
|---|---|
| Gene name | **clk-1** (C. elegans clock abnormal protein 1 / COQ7 ortholog) (pqac-00000040, pqac-00000043) |
| UniProt accession | **P48376** |
| Protein name | **NADPH-dependent 3-demethoxyubiquinone 3-hydroxylase, mitochondrial**; also called **protein CLK-1** or **ubiquinone biosynthesis monooxygenase COQ7** (pqac-00000000, pqac-00000001) |
| Enzymatic function | Catalyzes hydroxylation of demethoxyubiquinone during coenzyme Q biosynthesis; in C. elegans, loss of clk-1 prevents endogenous UQ9 production and causes DMQ9 accumulation, establishing CLK-1 as the DMQ hydroxylase step in the pathway (pqac-00000000, pqac-00000009, pqac-00000013) |
| EC number | **EC 1.14.13.253** |
| Substrate | **DMQ9 / 5-demethoxyubiquinone-9** (demethoxyubiquinone precursor of ubiquinone-9) (pqac-00000000, pqac-00000009, pqac-00000011) |
| Product | **UQ9 / ubiquinone-9 (coenzyme Q9)**; some descriptions also refer to formation of the hydroxylated intermediate en route to mature ubiquinone (pqac-00000009, pqac-00000013) |
| Cofactor / active site | **Carboxylate-bridged diiron center** that activates dioxygen for aromatic ring hydroxylation; catalytic activity is iron-sensitive and disrupted by manganese mismetallation (pqac-00000000, pqac-00000020, pqac-00000029, pqac-00000031) |
| Protein family | **COQ7 family**; conserved eukaryotic ubiquinone-biosynthetic hydroxylase family (pqac-00000040, pqac-00000043) |
| Structural features | Predicted/characterized **four-helix bundle** diiron protein with an additional **membrane-associating helix**; membrane-bound or peripherally membrane-associated hydroxylase (pqac-00000017, pqac-00000019) |
| Subcellular localization | Primarily **mitochondrial**, associated with the **inner mitochondrial membrane on the matrix side** for CoQ biosynthesis; evidence also supports **nuclear localization under stress/ROS conditions**, where CLK-1/COQ7 may regulate gene expression (pqac-00000002, pqac-00000003, pqac-00000005) |
| Pathway | **Coenzyme Q (ubiquinone) biosynthesis**; CLK-1/COQ7 functions in the late aromatic ring-modification steps and participates with COQ3/4/5/6/7/9 in the **COQ metabolon / CoQ synthome** (pqac-00000015, pqac-00000016, pqac-00000025) |
| Organism | **Caenorhabditis elegans** (worm) |
| Orthologs | Conserved across eukaryotes: **yeast Coq7p/Cat5p**, **mouse MCLK1**, **human COQ7**; functional complementation data support strong conservation (pqac-00000038, pqac-00000040, pqac-00000042, pqac-00000043) |


*Table: This table summarizes the core identity, enzymatic role, localization, structure, and pathway context of C. elegans CLK-1/COQ7. It is useful as a compact reference for functional annotation and for distinguishing clk-1 from unrelated similarly named genes.*