Pathways & interactions
ATPase, F1 complex, gamma subunit (IPR000131)
Short name: ATPase_F1-cplx_gsu
- ATPase, F1 complex, gamma subunit (IPR000131)
- Alternate F1F0 ATPase, F1 subunit gamma (IPR017709)
Transmembrane ATPases are membrane-bound enzyme complexes/ion transporters that use ATP hydrolysis to drive the transport of protons across a membrane. Some transmembrane ATPases also work in reverse, harnessing the energy from a proton gradient, using the flux of ions across the membrane via the ATPase proton channel to drive the synthesis of ATP.
There are several different types of transmembrane ATPases, which can differ in function (ATP hydrolysis and/or synthesis), structure (e.g., F-, V- and A-ATPases, which contain rotary motors) and in the type of ions they transport [PMID: 15473999, PMID: 15078220]. The different types include:
- F-ATPases (F1F0-ATPases), which are found in mitochondria, chloroplasts and bacterial plasma membranes where they are the prime producers of ATP, using the proton gradient generated by oxidative phosphorylation (mitochondria) or photosynthesis (chloroplasts).
- V-ATPases (V1V0-ATPases), which are primarily found in eukaryotic and they function as proton pumps that acidify intracellular compartments and, in some cases, transport protons across the plasma membrane [PMID: 20450191]. They are also found in bacteria [PMID: 9741106].
- A-ATPases (A1A0-ATPases), which are found in Archaea and function like F-ATPases, though with respect to their structure and some inhibitor responses, A-ATPases are more closely related to the V-ATPases [PMID: 18937357, PMID: 1385979].
- P-ATPases (E1E2-ATPases), which are found in bacteria and in eukaryotic plasma membranes and organelles, and function to transport a variety of different ions across membranes.
- E-ATPases, which are cell-surface enzymes that hydrolyse a range of NTPs, including extracellular ATP.
F-ATPases (also known as F1F0-ATPase, or H(+)-transporting two-sector ATPase) (EC:126.96.36.199) are composed of two linked complexes: the F1 ATPase complex is the catalytic core and is composed of 5 subunits (alpha, beta, gamma, delta, epsilon), while the F0 ATPase complex is the membrane-embedded proton channel that is composed of at least 3 subunits (A-C), nine in mitochondria (A-G, F6, F8). Both the F1 and F0 complexes are rotary motors that are coupled back-to-back. In the F1 complex, the central gamma subunit forms the rotor inside the cylinder made of the alpha(3)beta(3) subunits, while in the F0 complex, the ring-shaped C subunits forms the rotor. The two rotors rotate in opposite directions, but the F0 rotor is usually stronger, using the force from the proton gradient to push the F1 rotor in reverse in order to drive ATP synthesis [PMID: 11309608]. These ATPases can also work in reverse in bacteria, hydrolysing ATP to create a proton gradient.
The ATPase F1 complex gamma subunit forms the central shaft that connects the F0 rotary motor to the F1 catalytic core. The gamma subunit functions as a rotary motor inside the cylinder formed by the alpha(3)beta(3) subunits in the F1 complex [PMID: 16154570]. The best-conserved region of the gamma subunit is its C terminus, which seems to be essential for assembly and catalysis.
GO:0015986 ATP synthesis coupled proton transport
GO:0045261 proton-transporting ATP synthase complex, catalytic core F(1)