E7FI44 · HYD1A_PYRFU
- ProteinSulfhydrogenase 1 subunit alpha
- GenehydA
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids428 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
Function
function
Part of a bifunctional enzyme complex that functions as an NADPH-dependent hydrogen-evolving hydrogenase with sulfur-reducing activity. May play a role in hydrogen cycling during fermentative growth. Activity not exhibited with NAD. The alpha and delta subunits form the hydrogenase component that catalyzes the reduction of protons to evolve hydrogen.
Catalytic activity
- H2 + NADP+ = NADPH + H+
Cofactor
Protein has several cofactor binding sites:
Note: Binds 1 nickel ion per heterotetramer.
Kinetics
KM | SUBSTRATE | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|---|
5.3 mM | methyl viologen | |||||
79 μM | ferredoxin | |||||
0.08 mM | methylene blue | |||||
70 μM | ferredoxin (sodium dithionate as cosubstrate) | |||||
1 μM | ferredoxin (pyruvate and NADP as cosubstrates) | |||||
40 μM | NADP (pure H2 as cosubstrate) | |||||
0.2 mM | NADPH (H+ as cosubstrate) | |||||
3 mM | NADH (H+ as cosubstrate) | |||||
5 mM | methyl viologen (H2 as cosubstrate) |
Vmax | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|
2900 μmol/min/mg | with methyl viologen as substrate | ||||
18 μmol/min/mg | with ferredoxin as substrate (pyruvate and NADP as cosubstrates) | ||||
250 μmol/min/mg | with ferredoxin as substrate | ||||
261 μmol/min/mg | with methylene blue as substrate | ||||
67 μmol/min/mg | with ferredoxin as substrate (sodium dithionate as cosubstrate) | ||||
75 μmol/min/mg | with NADP as substrate (pure H2 as cosubstrate) | ||||
10 μmol/min/mg | with NADPH as substrate (H+ as cosubstrate) | ||||
6 μmol/min/mg | with NADPH as substrate (H+ as electron acceptor) | ||||
1.6 μmol/min/mg | with NADH as substrate (H+ as cosubstrate) | ||||
250 μmol/min/mg | with methyl viologen as substrate (H2 as cosubstrate) |
Measured for the whole complex.
pH Dependence
Optimum pH is 8 for hydrogenase activity at >95 degrees Celsius.
Temperature Dependence
Optimum temperature is greater than 95 degrees Celsius for hydrogenase activity. Stable up to 100 degrees Celsius. Loses 50% of activity at 80 degrees Celsius after 21 hour incubation.
Features
Showing features for binding site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 65 | Ni2+ (UniProtKB | ChEBI) | ||||
Sequence: C | ||||||
Binding site | 68 | Fe cation (UniProtKB | ChEBI) | ||||
Sequence: C | ||||||
Binding site | 68 | Ni2+ (UniProtKB | ChEBI) | ||||
Sequence: C | ||||||
Binding site | 418 | Ni2+ (UniProtKB | ChEBI) | ||||
Sequence: C | ||||||
Binding site | 421 | Fe cation (UniProtKB | ChEBI) | ||||
Sequence: C | ||||||
Binding site | 421 | Ni2+ (UniProtKB | ChEBI) | ||||
Sequence: C |
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | [Ni-Fe] hydrogenase complex | |
Cellular Component | cytoplasm | |
Molecular Function | ferredoxin hydrogenase activity | |
Molecular Function | hydrogen dehydrogenase (NADP+) activity | |
Molecular Function | nickel cation binding |
Keywords
- Molecular function
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameSulfhydrogenase 1 subunit alpha
- EC number
- Alternative names
Gene names
Organism names
- Strain
- Taxonomic lineageArchaea > Euryarchaeota > Thermococci > Thermococcales > Thermococcaceae > Pyrococcus
Accessions
- Primary accessionE7FI44
- Secondary accessions
Proteomes
Subcellular Location
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000420722 | 1-428 | Sulfhydrogenase 1 subunit alpha | |||
Sequence: MKNLYLPITIDHIARVEGKGGVEIIIGDDGVKEVKLNIIEGPRFFEAITIGKKLEEALAIYPRICSFCSAAHKLTALEAAEKAVGFVPREEIQALREVLYIGDMIESHALHLYLLVLPDYRGYSSPLKMVNEYKREIEIALKLKNLGTWMMDILGSRAIHQENAVLGGFGKLPEKSVLEKMKAELREALPLAEYTFELFAKLEQYSEVEGPITHLAVKPRGDAYGIYGDYIKASDGEEFPSEKYRDYIKEFVVEHSFAKHSHYKGRPFMVGAISRVINNADLLYGKAKELYEANKDLLKGTNPFANNLAQALEIVYFIERAIDLLDEALAKWPIKPRDEVEIKDGFGVSTTEAPRGILVYALKVENGRVSYADIITPTAFNLAMMEEHVRMMAEKHYNDDPERLKILAEMVVRAYDPCISCSVHVVRL |
Proteomic databases
Interaction
Subunit
Heterotetramer of alpha, beta, gamma and delta subunits. The nickel-containing alpha and delta subunits constitute the hydrogenase activity. The beta and gamma subunits (flavin-containing dimer) constitute the sulfur reductase activity.
Protein-protein interaction databases
Structure
Sequence
- Sequence statusComplete
- Length428
- Mass (Da)48,316
- Last updated2011-03-08 v1
- Checksum73856DFC716B5DCE
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
X75255 EMBL· GenBank· DDBJ | CAA53037.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
AE009950 EMBL· GenBank· DDBJ | AAL81018.1 EMBL· GenBank· DDBJ | Genomic DNA |