| [A] Methanosphaera stadtmanae (strain DSM 3091) | METST01255 | Q2NES4 | FrhA F420-reducing hydrogenase subunit alpha; COG3259, pfam00374 |
| [A] Methanocaldococcus jannaschii | METJA00028 | FRHA_METJA | Coenzyme F420 hydrogenase subunit alpha |
| [A] Methanococcus aeolicus (strain Nankai-3 / ATCC BAA-1280) | META301030 | A6UVV1 | Nickel-dependent hydrogenase large subunit |
| [A] Methanococcus maripaludis | METMP01382 | Q6LXG9 | Coenzyme F420-reducing hydrogenase subunit alpha |
| [A] Methanococcus maripaludis (strain C5 / ATCC BAA-1333) | METM500195 | A4FWD7 | Nickel-dependent hydrogenase, large subunit |
| [A] Methanococcus maripaludis (strain C6 / ATCC BAA-1332) | METM601277 | A9A9T1 | Coenzyme F420 hydrogenase, subunit alpha |
| [A] Methanococcus maripaludis (strain C7 / ATCC BAA-1331) | METM700620 | A6VGW8 | Nickel-dependent hydrogenase large subunit |
| [A] Methanococcus vannielii (strain SB / ATCC 35089 / DSM 1224) | METVS00680 | A6UQ26 | Nickel-dependent hydrogenase large subunit |
| [A] Methanopyrus kandleri | METKA00930 | Q8TWV0 | Coenzyme F420-reducing hydrogenase, alpha subunit |
| [A] Thermococcus onnurineus (strain NA1) | THEON01566 | B6YTV8 | Coenzyme F420 hydrogenase alpha subunit |
| [B] Clostridium botulinum (strain Alaska E43 / type E3) | CLOBA01517 | B2V1D6 | [Ni/Fe] hydrogenase, large subunit |
| [B] Clostridium botulinum (strain Eklund 17B / type B) | CLOBB01934 | B2TM83 | [Ni/Fe] hydrogenase, large subunit |