| Comment |
A multisubunit non-phosphorylated ATPase that is involved in the transport of ions. Large enzymes of mitochondria, chloroplasts and bacteria with a membrane sector (Fo, Vo, Ao) and a cytoplasmic-compartment sector (F1, V1, A1). The F-type enzymes of the inner mitochondrial and thylakoid membranes act as ATP synthases. All of the enzymes included here operate in a rotational mode, where the extramembrane sector (containing 3 alpha- and 3 beta-subunits) is connected via the delta-subunit to the membrane sector by several smaller subunits. Within this complex, the gamma- and epsilon-subunits, as well as the 9-12 c subunits rotate by consecutive 120_degree_ angles and perform parts of ATP synthesis. This movement is driven by the H+ electrochemical potential gradient. The V-type (in vacuoles and clathrin-coated vesicles) and A-type (archaeal) enzymes have a similar structure but, under physiological conditions, they pump H+ rather than synthesize ATP.
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