Pathway · 7 proteins
Glycolysis / Gluconeogenesis
Proteins of this group that KEGG places on its “Glycolysis / Gluconeogenesis” map for Aquifex aeolicus.
How it works
This map covers the central sugar route between glucose and three-carbon molecules, in both directions. Aquifex fixes carbon dioxide rather than eating sugar, so it mainly runs the route toward sugar (gluconeogenesis) to make the sugar phosphates it needs. The proteins here interconvert the six-carbon and three-carbon sugar phosphates, and the ferredoxin-dependent oxidoreductases link this route to the carbon-fixing cycle.
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 |
|---|---|---|---|---|---|
| Ferredoxin oxidoreductase beta subunit | — | — | — | 289 | Step named |
| Ferredoxin oxidoreductase beta subunit | — | — | — | 286 | Step named |
| Fructose-1,6-bisphosphate aldolase class II | — | — | Zn(2+) | 310 | Step named |
| ATP-dependent 6-phosphofructokinase | 2.7.1.11 | beta-D-fructose 6-phosphate + ATP = beta-D-fructose 1,6-bisphosphate + ADP + H(+) | Mg(2+) | 321 | Step named |
| Triosephosphate isomerase | 5.3.1.1 | D-glyceraldehyde 3-phosphate = dihydroxyacetone phosphate | — | 247 | Step named |
| Probable 2,3-bisphosphoglycerate-independent phosphoglycerate mutase | 5.4.2.12 | (2R)-2-phosphoglycerate = (2R)-3-phosphoglycerate | — | 407 | Step named |
| Bifunctional phosphoglucose/phosphomannose isomerase | 5.3.1.8; 5.3.1.9 | alpha-D-glucose 6-phosphate = beta-D-fructose 6-phosphate | D-fructose 6-phosphate | 320 | Step named |
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 |
|---|---|---|---|---|---|
| Glyceraldehyde-3-phosphate dehydrogenaseHome: Sugar-phosphate supply | 1.2.1.12 | D-glyceraldehyde 3-phosphate + phosphate + NAD(+) = (2R)-3-phospho-glyceroyl phosphate + NADH + H(+) | — | 342 | Step named |
| Ferredoxin oxidoreductase alpha subunitHome: Sugar-phosphate supply | — | — | — | 389 | Step named |
| Ferredoxin oxidoreductase gamma subunitHome: Pyruvate and acetyl-CoA | — | — | — | 230 | Step named |
| Phosphoglycerate kinaseHome: Sugar-phosphate supply | 2.7.2.3 | (2R)-3-phosphoglycerate + ATP = (2R)-3-phospho-glyceroyl phosphate + ADP | — | 397 | Step named |
| Ferredoxin oxidoreductase alpha subunitHome: Sugar-phosphate supply | — | — | — | 404 | Step named |
| Ferredoxin oxidoreductase gamma subunitHome: Pyruvate and acetyl-CoA | — | — | — | 241 | 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 |
| 2-amino-3,7-dideoxy-D-threo-hept-6-ulosonate synthaseHome: Phenylalanine, tyrosine and tryptophan biosynthesis | 2.2.1.10 | 1-deoxy-D-threo-hexo-2,5-diulose 6-phosphate + L-aspartate 4-semialdehyde = 2,3-dioxopropyl phosphate + 2-amino-2,3,7-trideoxy-D-lyxo-hept-6-ulosonate | 1-deoxy-D-threo-hexo-2,5-diulose 6-phosphate | 264 | Step named |
| Dihydrolipoyl dehydrogenaseHome: Glycine, serine and threonine metabolism | 1.8.1.4 | N(6)-[(R)-dihydrolipoyl]-L-lysyl-[protein] + NAD(+) = N(6)-[(R)-lipoyl]-L-lysyl-[protein] + NADH + H(+) | — | 465 | Step named |
| EnolaseHome: Not yet placed in a pathway | 4.2.1.11 | (2R)-2-phosphoglycerate = phosphoenolpyruvate + H2O | Mg(2+) | 426 | Step named |
| Fructose-1,6-bisphosphate aldolase/phosphataseHome: Fructose and mannose metabolism | 3.1.3.11; 4.1.2.13 | beta-D-fructose 1,6-bisphosphate + H2O = beta-D-fructose 6-phosphate + phosphate | Mg(2+), beta-D-fructose 1,6-bisphosphate | 381 | Unspecified |
| Propionate--CoA ligaseHome: Glyoxylate and dicarboxylate metabolism | — | acetate + ATP + CoA = acetyl-CoA + AMP + diphosphate | — | 510 | Unspecified |
Origins
Could the sugars and three-carbon intermediates of this pathway have formed without enzymes?
In the formose reaction, formaldehyde condenses under alkaline conditions with a catalyst such as calcium. It gives glyceraldehyde, an intermediate of glycolysis, and larger sugars, and Deamer considers it a plausible prebiotic source of carbohydrates.
The formose reaction produces hundreds of compounds. Ribose, for example, is only a tiny fraction unless borate is added to stabilise it.
Forming some of the same small sugars is not forming the pathway: the cell converts them step by step with seven enzymes in this group, and the many side products of the uncontrolled reaction would compete with the useful ones.
From the books: Deamer, Assembling Life, p. 41.
The wider question for this part of the cell: origins for building carbon into molecules.
Sources
- KEGG map aae00010 (enzymes of this organism highlighted)
Other pathways in this group: Reductive TCA machinery · Sugar-phosphate supply · Pyruvate and acetyl-CoA · Lipid A and outer envelope · Ribose and PRPP supply · Amino sugar and nucleotide sugar metabolism · Pentose phosphate pathway · Not yet placed in a pathway