ATP synthase as a rotatory engine:

The ATP synthase can be seen as spherical projections from the inner membrane.  If  mitochondria   are  subjected  to  sonic  disruption,  submitochondrial vesicles  are established  in that  the spheres  of the ATP  synthase  point  outward. In the year of 1960, Racker showed in which the spheres can be erased and in which the isolated spheres hydrolyze ATP, which is, the spheres have ATPase activity called F₁.  The  exposed  submitochondrial vesicles,  devoid  of  the  F₁ ATPase,  can  since  transport  electrons  along  the  electron  transport  chain  but cannot  synthesize  ATP.  These stripped submitochondrial vesicles contain the other main elements of the ATP synthase, known as F₀ coupling factor 0 that spans the inner mitochondrial membrane. Because it is composed of these two main component   parts, ATP synthase is also called F₀F₁ ATPase.  The whole complex harnesses the energy released through electron transport to drive ATP synthesis while alone, without coupling to electron transport, the F₁ parts hydrolyzes ATP.

The F₁  ATPase consists of five kinds of polypeptides  in the subsequent ratio: α3, β3, γ, δ,  ε.  The six α  and β subunits  are arranged alternately  in a ring and with a middle stalk formed through the γ and ε subunits. The F₀ consists of a ring of 10 to 14 c subunits sitting in the inner mitochondrial membrane. This  contacts  a single a subunit which links to two b subunits and the single δ subunit to establish a long column  which  connects  to the  head  of the  F₁ ATPase.  This whole structure, the F₀F₁ ATPase, is a remarkable molecular motor.  In during   ATP synthesis, protons flow by a channel build at the interface among the subunit and c subunits and this causes the c subunit ring to spin associatively to the static a subunit. Therefore the c ring acts as a 'rotor' and the subunit as a 'stator'. As

Figure:  Sonic disruption (sonication) of mitochondria produces submitochondrial vesicles.

Figure:   Schematic representation of the ATP synthase complex.

the  c subunit  ring  rotates and it turns  the  γ subunit  stalk,  that  thus  turns rapidly inside the αβ ring. The αβ ring cannot rotate because it is held in place through the arm of the two δ subunit and b subunits.

The three β subunits in the αβ ring can bind inorganic phosphate and ADP. As the γ subunit  rotates  inside  the αβ  ring and  the mechanical  energy  is used  to drive ATP synthesis; that three molecules of ATP are synthesized for each 360 degree rotation of the γ subunit  which  equates  to over  1000  molecules  per second!. How is the ATP build?  According to the binding-charge mechanism of Paul Boyer while the rotation causes the γ subunit to turn past the three β subunits and the protein conformation of the three nucleotide binding sites of the β subunits changes by variant states that causes ADP to be bound, then phosphorylated and then released as ATP So the mechanical energy of the rotating γ subunit is used to drive protein conformational modifies which in turn lead to ATP synthesis.