[NiFe] Group 1h-hydrogenase

This entry was last updated at: Feb. 9, 2018, 3:51 a.m.

Properties
Group [NiFe] Group 1: Respiratory H2-uptake [NiFe] hydrogenases
Subgroup [NiFe] Group 1h: Actinobacteria-type
Function Hydrogenotrophic respiration using O2 as terminal electron acceptor. Enzyme scavenges electrons from atmospheric H2 to fuel respiratory chain during carbon-starvation. Route of electron transfer unresolved.
Activity H2-uptake (unidirectional, high-affinity)
Oxygen tolerance O2-tolerant or O2-insensitive
Localisation Membrane-associated?
Distribution
Ecosystem distribution Upland soils, plant tissues, possibly surface waters
Taxonomic distribution Widespread among obligately aerobic soil bacteria, especially Actinobacteria, Acidobacteria, and Chloroflexi
Genetic Organisation

e.g. Mycobacterium smegmatis (WP_003893634.1):

Architecture
Structures
  • 5AA5 (Ralstonia eutropha, 2.5 Å resolution, active)
Subunits 3?
Subunit description HyhL (hydrogenase large subunit)
HyhS (hydrogenase small subunit) HyhE (putative iron-sulfur protein and proposed physiological electron acceptor)
Catalytic site [NiFe]-centre
FeS clusters Proximal: 3Cys1Asp[4Fe4S]
Medial: 4Cys[4Fe4S]
Distal: 3Cys1His[4Fe4S]
Important Notes
The Robiginitalea biformata and Sulfolobus islandicus enzymes are relatively distantly related to the main group. No studies have yet tested whether these enzymes have a H2-scavenging role like other Group 1h [NiFe]-hydrogenases. They may instead represent founding members of a functionally-distinct lineage.
Sequences in this class
NCBI AccessionOrganismHydrogenase ClassPhylumOrderActivity (Predicted)Oxygen Tolerance (Predicted)Subunits (Predicted)Metal Centres (Predicted)Accessory Subunits (Predicted)
WP_014512387.1Sulfolobus islandicus[NiFe] Group 1hCrenarchaeotaSulfolobalesAerobic UptakeTolerant3[NiFe]-centre, 3 x [4Fe4S] clusters[FeS] protein
WP_013132859.1Thermobispora bispora[NiFe] Group 1hActinobacteriaActinomycetalesAerobic UptakeTolerant3[NiFe]-centre, 3 x [4Fe4S] clusters[FeS] protein
WP_015922819.1Thermomicrobium roseum[NiFe] Group 1hChloroflexiThermomicrobialesAerobic UptakeTolerant3[NiFe]-centre, 3 x [4Fe4S] clusters[FeS] protein
WP_012854897.1Thermomonospora curvata[NiFe] Group 1hActinobacteriaActinomycetalesAerobic UptakeTolerant3[NiFe]-centre, 3 x [4Fe4S] clusters[FeS] protein

Literature

Genetics:

Physiology:

Biochemistry: