Pathway · 2 proteins
Other carbon fixation pathways
Proteins of this group that KEGG places on its “Other carbon fixation pathways” map for Aquifex aeolicus.
How it works
This map collects carbon-fixing routes other than the main ones. The two Aquifex proteins KEGG places here, an iron-sulfur subunit like that of DMSO reductase and an NADH oxidase, have no established role in carbon fixation in the minimal cell.
Grouped by KEGG pathway map. The explanation above is the atlas’s own; the map itself covers more organisms than Aquifex.
Its proteins
| Protein | EC | Reaction (UniProt) | Metal or cluster | Amino acids | Certainty |
|---|---|---|---|---|---|
| Dimethylsulfoxide reductase chain B | — | — | — | 170 | Unspecified |
| NADH oxidase | — | — | — | 474 | Unspecified |
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 |
|---|---|---|---|---|---|
| Ferredoxin oxidoreductase alpha subunitHome: Sugar-phosphate supply | — | — | — | 389 | Step named |
| Ferredoxin oxidoreductase beta subunitHome: Glycolysis / Gluconeogenesis | — | — | — | 289 | Step named |
| Ferredoxin oxidoreductase gamma subunitHome: Pyruvate and acetyl-CoA | — | — | — | 230 | Step named |
| Ferredoxin oxidoreductase alpha subunitHome: Sugar-phosphate supply | — | — | — | 404 | Step named |
| Ferredoxin oxidoreductase beta subunitHome: Glycolysis / Gluconeogenesis | — | — | — | 286 | Step named |
| Ferredoxin oxidoreductase gamma subunitHome: Pyruvate and acetyl-CoA | — | — | — | 241 | Step named |
| Succinyl-CoA ligase beta subunitHome: Reductive TCA machinery | — | oxaloacetate + acetyl-CoA + ADP + phosphate = citrate + ATP + CoA | — | 436 | Step named |
| citrate synthase (unknown stereospecificity)Home: Reductive TCA machinery | 2.3.3.16 | — | — | 259 | Step named |
| Isocitrate dehydrogenase [NADP]Home: Reductive TCA machinery | 1.1.1.42 | D-threo-isocitrate + NADP(+) = 2-oxoglutarate + CO2 + NADPH | Mg(2+), Mn(2+) | 426 | Step named |
| Succinate--CoA ligase [ADP-forming] subunit betaHome: Reductive TCA machinery | 6.2.1.5 | succinate + ATP + CoA = succinyl-CoA + ADP + phosphate | Mg(2+) | 385 | Step named |
| Succinate--CoA ligase [ADP-forming] subunit alphaHome: Reductive TCA machinery | 6.2.1.5 | succinate + ATP + CoA = succinyl-CoA + ADP + phosphate | — | 305 | Step named |
| C-terminal fumarate hydratase, class IHome: Not yet placed in a pathway | — | — | — | 185 | Step named |
| Fumarate hydratase (Fumarase)Home: Reductive TCA machinery | — | — | — | 281 | Step named |
| Malate dehydrogenase 1Home: Reductive TCA machinery | 1.1.1.37 | (S)-malate + NAD(+) = oxaloacetate + NADH + H(+) | — | 335 | Step named |
| Aconitate hydratase AHome: Reductive TCA machinery | 4.2.1.3 | citrate = D-threo-isocitrate | [4Fe-4S] cluster | 659 | Step named |
| Succinyl-CoA ligase alpha subunitHome: Reductive TCA machinery | — | — | — | 368 | Step named |
| succinate dehydrogenaseHome: Reductive TCA machinery | 1.3.5.1 | — | [2Fe-2S] cluster, [3Fe-4S] cluster, [4Fe-4S] cluster | 230 | Step named |
| Succinate dehydrogenase flavoprotein subunitHome: Reductive TCA machinery | 1.3.5.1 | a menaquinone + succinate = a menaquinol + fumarate | — | 571 | Step named |
| Phosphoenolpyruvate synthaseHome: Pyruvate and acetyl-CoA | 2.7.9.2 | pyruvate + ATP + H2O = phosphoenolpyruvate + AMP + phosphate + 2 H(+) | Mg(2+) | 856 | Step named |
| Acetyl-coenzyme A carboxylase carboxyl transferase subunit alphaHome: Lipid and cofactor connections | 2.1.3.15 | N(6)-carboxybiotinyl-L-lysyl-[protein] + acetyl-CoA = N(6)-biotinyl-L-lysyl-[protein] + malonyl-CoA | — | 323 | Step named |
| Biotin carboxyl carrier protein of acetyl-CoA carboxylaseHome: Lipid and cofactor connections | — | — | — | 154 | Step named |
| 5,10-methylenetetrahydrofolate reductaseHome: Folate and pterin chemistry | 1.5.1.54 | (6S)-5-methyl-5,6,7,8-tetrahydrofolate + NAD(+) = (6R)-5,10-methylene-5,6,7,8-tetrahydrofolate + NADH + H(+) | — | 296 | Step named |
| Biotin carboxylaseHome: Lipid and cofactor connections | — | — | — | 477 | Step named |
| Oxaloacetate decarboxylase alpha chainHome: Pyruvate metabolism | — | — | — | 620 | Step named |
| Biotin carboxylaseHome: Lipid and cofactor connections | 6.3.4.14 | N(6)-biotinyl-L-lysyl-[protein] + hydrogencarbonate + ATP = N(6)-carboxybiotinyl-L-lysyl-[protein] + ADP + phosphate + H(+) | — | 444 | Step named |
| Bifunctional protein FolDHome: Folate and pterin chemistry | 1.5.1.5; 3.5.4.9 | (6R)-5,10-methylene-5,6,7,8-tetrahydrofolate + NADP(+) = (6R)-5,10-methenyltetrahydrofolate + NADPH | — | 291 | Step named |
| Acetyl-coenzyme A carboxylase carboxyl transferase subunit betaHome: Lipid and cofactor connections | 2.1.3.15 | N(6)-carboxybiotinyl-L-lysyl-[protein] + acetyl-CoA = N(6)-biotinyl-L-lysyl-[protein] + malonyl-CoA | Zn(2+) | 276 | Step named |
| Propionate--CoA ligaseHome: Glyoxylate and dicarboxylate metabolism | — | acetate + ATP + CoA = acetyl-CoA + AMP + diphosphate | — | 510 | Unspecified |
Origins
Could carbon dioxide or carbon monoxide have been fixed on minerals before enzymes?
How it was discovered
- 1997Huber and Wächtershäuser make activated acetic acid from carbon monoxide and methyl mercaptan on nickel-iron sulfide under conditions they consider primordial.Huber & Wächtershäuser, Science 276:245–247 (1997); Deamer, Assembling Life, p. 49
Metal sulfides have been tested for their ability to catalyse carbon fixation (Cody et al. 2004), and an activated two-carbon compound has been made on them.
These experiments use chosen gases and minerals and give single steps. The two Aquifex proteins KEGG places on this map have no established role in the minimal cell.
From the books: Deamer, Assembling Life, p. 49; Zaikowski & Friedrich (eds.), Chemical Evolution across Space and Time, p. 13.
The wider question for this part of the cell: origins for conserved, but we cannot say what they do.
Sources
- KEGG map aae00720 (enzymes of this organism highlighted)
Other pathways in this group: tRNA charging · Nutrient and metabolic state · Biosynthesis of various nucleotide sugars · Purine metabolism · Bacterial secretion system · Glyoxylate and dicarboxylate metabolism · Starch and sucrose metabolism · Homologous recombination · Fructose and mannose metabolism · Streptomycin biosynthesis · Nicotinate and nicotinamide metabolism · Not yet placed in a pathway