TABLE 1.
Comparison of cytosolic hydrogenases from hyperthermophilic archaea
| Property | T. kodakaraensis hydrogenase | T. litoralis hydrogenase | T. stetteri hydrogenase | T. celer hydrogenase |
P. furiosus
|
|
|---|---|---|---|---|---|---|
| Hydrogenase I | Hydrogenase II | |||||
| Subunit composition | αβγδ | αβγδ | Not determined | αβ | αβγδ | αβγδ |
| Gene isolation | Yes | Yes | Not performed | Not performed | Yes | Yes |
| Sequence identity with T. kodakaraensis hydrogenase | 100% | 81.7% | Not determined | Not determined | 83.7% | 44.2% |
| Holoenzyme | (αβγδ)na | αβγδ | Not determined | (αβ)2 | αβγδ | (αβγδ)2 |
| Ni content | 0.8 ± 0.1b | 0.9 ± 0.1 | 1d | 1.9-2.3 | 0.8 ± 0.1e | 0.9 ± 0.1b |
| Fe content | 22.3 ± 0.7b | 22.0 ± 1.0 | 13d | 24-30 | 26 ± 2.5e | 21 ± 1.6b |
| Acid-labile sulfide | 21.1 ± 0.7b | 22.0 ± 2.0 | Not determined | 24-36 | 20 ± 3.2e | 19 ± 2.1b |
| Flavin cofactor species | FAD | Not determined | Flavin mononucleotide | Not determined | FAD | FAD |
| Flavin cofactor content | 1b | Not determined | Not determined | Not determined | 1 | 1b |
| H2 uptake (U/mg at 80°C) | ||||||
| NADP+ (1 mM) | 48.7 | Not determined | 0 | Not determined | 75 | 0.3 |
| Methyl viologen (1 mM) | 319 | 110c | 20,000 (98°C) | 12,900 (88°C) | 250 | 11 |
| H2 evolution (U/mg at 80°C) | ||||||
| NADPH (1 mM) | 2.72 | Not determined | Not determined | Not determined | 10 | 0.2 |
| Methyl viologen (1 mM) | 283 | 33c | Not determined | 9,160 (88°C) | 290 | 40 |
| Reference(s) | This work | 29 | 47 | 3 | 5,19 | 19, 21 |
a
n ≥ 3.
b
per αβγδ.
c
Vmax value.
d
13 mol of Fe per mol of Ni.
e
Original data (5) were recalculated according to the molecular mass determined from the sequence.