Pathway · 5 proteins
NiFe-hydrogenase maturation
Hyp and maturation proteins support assembly of NiFe enzymes.
How it works
- Hyp proteins, nickel-associated factors, maturation chaperones and a hydrogenase-processing protease support construction of a NiFe-hydrogenase active site.
- In a representative maturation mechanism, dedicated machinery prepares the iron-ligand moiety, delivers nickel and coordinates cofactor incorporation into a precursor hydrogenase. Proteolytic processing can follow appropriate maturation.
- This is distinct from general Fe–S scaffold assembly, although a mature hydrogenase complex can also require Fe–S electron-transfer subunits. The gene list does not establish every ligand-production or metal-transfer step in VF5.
Grouped by the atlas’s curated pathway map. The table order is not a proven reaction order.
Its proteins
| Protein | EC | Reaction (UniProt) | Metal or cluster | Amino acids | Certainty |
|---|---|---|---|---|---|
| Hydrogenase expression/formation protein | — | — | — | 332 | System only |
| Hydrogenase expression/formation protein HypD | — | — | — | 380 | System only |
| HupD hydrogenase related function | — | — | Ni(2+) | 162 | System only |
| Hydrogenase expression/formation protein B | — | — | — | 259 | System only |
| Carbamoyltransferase | 6.2.-.- | C-terminal L-cysteinyl-[HypE protein] + carbamoyl phosphate + ATP + H2O = C-terminal S-carboxamide-L-cysteinyl-[HypE protein] + AMP + phosphate + diphosphate + H(+) | — | 746 | Step named |
Also part of this pathway
These proteins are described under another pathway, but also take part here.
| Protein | EC | Reaction (UniProt) | Metal or cluster | Amino acids | Certainty |
|---|---|---|---|---|---|
| Hydrogenase maturation factor HypAHome: Not yet placed in a pathway | — | — | Ni(2+), Zn(2+) | 115 | Step named |
Origins
How could the nickel-iron centre of hydrogenase have been built before its maturation proteins existed?
None of the books searched discusses hydrogenase maturation.
The centre carries carbon monoxide and cyanide on its iron. HypF and HypE make the cyanide, HypC and HypD hold the iron while its ligands are attached, HypB delivers nickel, and a protease trims the finished subunit. The maturation proteins and the hydrogenase must all be present before the cell can use its food, hydrogen.
The wider question for this part of the cell: origins for loading metals into enzymes.
Sources
- Atlas pathway grouping from the VF5 reference-genome system map (Deckert et al. 1998; Braakman & Smith 2014)
Other pathways in this group: Metal installation · Not yet placed in a pathway