Question

Describe the overall structure of the F₁ and F₀ components of ATP synthase. Which parts move? Which are stationary? Which are mostly stationary but undergo conformational changes?

Short answer

F₀ is a transmembrane protein that cannot be dissolved in water and has up to eight different kinds of subunits. F₁ is a peripheral membrane protein that is water soluble and has five different types of subunits. The $\mathrm{\alpha }$and $\mathrm{\beta }$ subunit of F₁ subunit are stationary and is responsible for ADP binding. The c subunit of F₀subunit is moving as it allows the rotor ring. Also, the α, β, $\mathrm{\gamma }$, $\mathrm{\delta }$, and$\mathrm{\epsilon }$ subunits are stationary at the start and later undergo conformational changes when c subunit rotates.

Step-by-step solution

Define ATP synthase

ATP synthase is an enzyme that catalyzes the conversion of ADP and Pi into the energy storage molecule ATP. ATP synthase is made up of two regions: F₀ and F₁. The F₀ and F₁ pathway allows protons to travel across the membrane.

Step 2: Parts of ATP synthase

The F₁ is a part of ATP synthase and is hydrophilic. It is responsible for hydrolyzing ATP. The unit protrudes into the mitochondrial matrix space. Alpha and beta subunits combine to form a hexamer with six binding sites. Three of them bind ADP but are catalytically inactive. The ATP production is catalysed by the other three subunits. Remaining F₁ sub-units $\mathrm{\gamma },\mathrm{\vartheta },\mathrm{\epsilon }$are member of a rotational motor mechanism. $\mathrm{\gamma }$sub-unit allows $\mathrm{\beta }$to go through conformational changes thereby facilitate ATP to be bound and released upon synthesis.

The ATP synthase F₀ region is a protein pore implanted in the mitochondrial membrane. It is divided into three parts: a, b, and c. The rotor ring is made up of six c subunits, and subunit b is a stalk that connects to F₁OSCP and inhibits the $\mathrm{\alpha \beta }$hexamer from spinning. Subunit a joins the rings b and c.

F₀ is an eight-subunit water-soluble protein containing a transmembrane ring. When protonated and deprotonated, the ring takes on a tetramer shape with a helix loop helix protein. Then the ring undergoes conformational changes and forces nearby subunits to rotate and spin of protein.