proton-transporting ATP synthase complex

Definition

Target type: cellularcomponent

A proton-transporting two-sector ATPase complex that catalyzes the phosphorylation of ADP to ATP during oxidative phosphorylation. The complex comprises a membrane sector (F0) that carries out proton transport and a cytoplasmic compartment sector (F1) that catalyzes ATP synthesis by a rotational mechanism; the extramembrane sector (containing 3 a and 3 b subunits) is connected via the d-subunit to the membrane sector by several smaller subunits. Within this complex, the g and e subunits and the 9-12 c subunits rotate by consecutive 120 degree angles and perform parts of ATP synthesis. This movement is driven by the hydrogen ion electrochemical potential gradient. [ISBN:0198547684, ISBN:0716743663]

Proton-transporting ATP synthase complex, also known as F-type ATPase, is a multi-subunit enzyme found in the mitochondrial inner membrane (in eukaryotes) and the plasma membrane of bacteria. It plays a crucial role in cellular energy production by utilizing the proton gradient across the membrane to synthesize ATP from ADP and inorganic phosphate. The complex is composed of two main components:

* **F1 complex:** Located in the mitochondrial matrix (in eukaryotes) or the cytoplasm (in bacteria), this part of the complex is responsible for ATP synthesis. It consists of five different subunits: alpha, beta, gamma, delta, and epsilon. The alpha and beta subunits form a hexameric structure that binds and hydrolyzes ATP. The gamma subunit acts as a rotor, while the delta and epsilon subunits regulate the activity of the complex.

* **F0 complex:** Embedded in the inner mitochondrial membrane (in eukaryotes) or the plasma membrane (in bacteria), this component is responsible for proton translocation. It consists of three main subunits: a, b, and c. The c subunits form a ring that rotates as protons flow through it. The a subunit forms a channel that allows protons to enter the ring, while the b subunits act as stator units, anchoring the F0 complex to the membrane.

The mechanism of ATP synthesis by proton-transporting ATP synthase involves the following steps:

1. **Proton movement:** Protons move from the intermembrane space (in eukaryotes) or the periplasm (in bacteria) across the membrane through the F0 complex.
2. **Rotation:** The movement of protons causes the c subunit ring to rotate.
3. **Energy transfer:** The rotation of the c subunit ring is coupled to the rotation of the gamma subunit in the F1 complex.
4. **ATP synthesis:** The rotation of the gamma subunit within the alpha and beta subunits of the F1 complex induces conformational changes that drive the synthesis of ATP from ADP and inorganic phosphate.

This intricate and tightly regulated process ensures that the energy derived from the proton gradient is efficiently harnessed to produce the essential cellular energy currency, ATP.'
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Proteins (1)

Compounds (5)