Pathway · 9 proteins
ATP synthesis
F0F1 subunits couple ion flow to ATP synthesis.
How it works
- The F0 sector (subunits A, B and C) forms the membrane rotor, and the F1 sector (alpha, beta, gamma, delta and epsilon) carries the catalytic nucleotide sites.
- Ion flow through F0 drives rotation of the gamma subunit, which pushes the beta subunits through the conformational cycle that makes ATP from ADP and phosphate.
- The synthase is reversible: the same enzyme hydrolyses ATP to pump ions when the gradient collapses. The annotation lists the subunits, not the operating direction.
Grouped by the atlas’s curated pathway map. The table order is not a proven reaction order.
Its proteins
| Protein | EC | Reaction (UniProt) | Metal or cluster | Amino acids | Certainty |
|---|---|---|---|---|---|
| ATP synthase subunit b | — | — | — | 144 | Step named |
| ATP synthase subunit b | — | — | — | 185 | Step named |
| ATP synthase subunit delta | — | — | — | 181 | Step named |
| ATP synthase subunit c | — | — | — | 100 | Step named |
| ATP synthase subunit a | — | — | — | 216 | Step named |
| ATP synthase subunit beta | 7.1.2.2 | ATP + H2O + 4 H(+)(in) = ADP + phosphate + 5 H(+)(out) | — | 478 | Step named |
| ATP synthase gamma chain | — | — | — | 291 | Step named |
| ATP synthase epsilon chain | — | — | — | 132 | Step named |
| ATP synthase subunit alpha | 7.1.2.2 | ATP + H2O + 4 H(+)(in) = ADP + phosphate + 5 H(+)(out) | — | 503 | Step named |
Origins
How could ATP have been made before ATP synthase existed?
How it was discovered
- 1997Paul Boyer shares the Nobel Prize for explaining how ATP synthase works by rotation; Peter Mitchell had received one in 1978 for the chemiosmotic theory.Deamer, Assembling Life, p. 91
Proposed early energy sources include light, chemical energy at volcanic sites and redox reactions. High concentrations of polyphosphate in volcanic condensates and steam vents suggest it could have served as an early energy source.
Deamer judges that none of the proposed ideas has advanced very far beyond conjecture and that the evidence has not led to any consensus.
ATP synthase is a rotary motor: a ring spun by protons drives a central stalk that forces ATP out of the head. Nine proteins of the minimal set make it up, and it works only in a sealed membrane with a gradient built by other proteins.
From the books: Deamer, Assembling Life, p. 91; Nelson & Cox, Lehninger Principles of Biochemistry, p. 511.
The wider question for this part of the cell: origins for turning hydrogen into usable energy.
Sources
- Atlas pathway grouping from the VF5 reference-genome system map (Deckert et al. 1998; Braakman & Smith 2014)
Other pathways in this group: Quinone-linked electron transfer · Oxygen reduction · Hydrogen oxidation · Oxidative phosphorylation · Not yet placed in a pathway