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The structure of the intact ATP synthase is currently known at low-resolution from electron cryo-microscopy (cryo-EM) studies of the complex. The cryo-EM model of ATP synthase suggests that the peripheral stalk is a flexible structure that wraps around the complex as it joins F 1 to F O.
The alpha/A and beta/B subunits can each be divided into three regions, or domains, centred on the ATP-binding pocket, and based on structure and function. The central domain contains the nucleotide-binding residues that make direct contact with the ADP/ATP molecule.
As the protons bind to the subunits of the F o domains, they cause parts of it to rotate. This rotation is propagated by a 'camshaft' to the F 1 domain. ADP and Pi (inorganic phosphate) bind spontaneously to the three β subunits of the F 1 domain, so that every time it goes through a 120° rotation ATP is released (rotational catalysis).
ATP synthase is the enzyme that makes ATP by chemiosmosis. It allows protons to pass through the membrane and uses the free energy difference to convert phosphorylate adenosine diphosphate (ADP) into ATP. The ATP synthase contains two parts: CF0 (present in thylakoid membrane) and CF1 (protrudes on the outer surface of thylakoid membrane).
The protons return to the mitochondrial matrix through the protein ATP synthase. The energy is used in order to rotate ATP synthase which facilitates the passage of a proton, producing ATP. A pH difference between the matrix and intermembrane space creates an electrochemical gradient by which ATP synthase can pass a proton into the matrix ...
Some ATPases work in reverse, using the energy from the hydrolysis of ATP to create a proton gradient. There are different types of ATPases, which can differ in function (ATP synthesis and/or hydrolysis), structure (F-, V- and A-ATPases contain rotary motors) and in the type of ions they transport. [2] [3]
Mechanism of ATP synthase. ATP is shown in red, ADP and phosphate in pink and the rotating γ subunit in black. This ATP synthesis reaction is called the binding change mechanism and involves the active site of a β subunit cycling between three states. [77] In the "open" state, ADP and phosphate enter the active site (shown in brown in the ...
ATP synthase is composed of two linked multi-subunit complexes: the soluble catalytic core, F1, and the membrane-spanning component, Fo, comprising the proton channel. The catalytic portion of mitochondrial ATP synthase consists of 5 different subunits (alpha, beta, gamma, delta, and epsilon) assembled with a stoichiometry of 3 alpha, 3 beta ...