What is rotational catalysis?

A proposed partial mechanism of ATP synthase in which a transmembrane ion channel, which is a hexamer composed of a ring of alternating and subunits, in which a single subunit rotates, binding ADP and Pi and displacing ATP.Block, S.M. (1997) Nature (London) 386, 217-219; Junge, W., Lill, H.

What does the rotation of ATP synthase do?

The Fo rotor spins in response to proton (H+) flow down a concentration gradient across the membrane. This rotation causes the central stalk (axle) to rotate, altering the conformation of components of the F1 base, driving the synthesis of ATP.

What is the rotating part of the ATP synthase enzyme?

ATP synthase synthesizes ATP from ADP and inorganic phosphate by a unique rotary mechanism where two subcomplexes move relative to each other, powered by a proton or sodium gradient. The non-rotating parts of the machinery are held together by the “stator stalk”.

How is ATP synthesized by rotary motor?

(A) ATP synthase consists of two rotary motors connected back-to-back. Normally the proton-driven F0 forces F1 in reverse (clockwise) and ATP is synthesized in F1. This step is divided into sub-steps of 80° and 40°, triggered by ATP binding and by hydrolysis or product release, respectively [5, 8].

Where is the rotation engine of ATP synthase located?

Rotation engine of ATP synthase. Located within the thylakoid membrane and the inner mitochondrial membrane, ATP synthase consists of two regions F O and F 1. F O causes rotation of F 1 and is made of c-ring and subunits a, two b, F6. F 1 is made of α, β, γ, and δ subunits.

How does the alternating catalytic model of ATP synthase work?

According to the current model of ATP synthesis (known as the alternating catalytic model), the transmembrane potential created by (H+) proton cations supplied by the electron transport chain, drives the (H+) proton cations from the intermembrane space through the membrane via the F O region of ATP synthase.

How many cycles does F 0f 1 ATP synthase perform?

Rotation of the F 0F 1 ATP synthase γ subunit drives each of the three catalytic sites through their reaction pathways. The enzyme completes three cycles and synthesizes or hydrolyzes three ATP for each 360° rotation of the γ subunit.

What are the molecular mechanisms of rotational catalysis?

Rotational catalysis In the late 1970s, Boyer [29], [30] proposed the ‘binding change mechanism’, a model that arose from observations ‘that energy input was involved principally in change in the binding of reactants at catalytic sites by indirect coupling’ [31].