What happens when ATP synthase is reversed?

Function. The ATP synthase enzymes have been remarkably conserved through evolution. The reaction catalyzed by ATP synthase is fully reversible, so ATP hydrolysis generates a proton gradient by a reversal of this flux.

Which conformation of the F1 subunit of ATP synthase releases ATP?

TIGHT conformation
The TIGHT conformation produces ATP (ADP + Pi —> ATP) but is incapable of releasing this catalytic product. Only when the TIGHT to OPEN conformational change is induced can the beta subunit release ATP.

What determines the direction of rotation of ATP synthase?

Under physiological condition where the electrochemical potential of the protons is large enough to surpass the free energy of ATP hydrolysis, Fo forcibly rotates the γ-subunit in the clockwise direction and then F1 catalyses the reverse reaction, i.e. ATP synthesis which is the principle physiological function of ATP …

What happens when mitochondrial ATP synthase is inhibited?

Inhibition of the ATP synthase compromises the output of ATP by OXPHOS and rewires energy metabolism to an enhanced glycolysis.

Why do isolated F1 subunits of ATP synthase catalyze ATP hydrolysis?

The enzyme is reversible. If protons flow down a concentration gradient through Fo, ATP is synthesized by F1. Alternatively, ATP hydrolysis by F1 leads to transport of protons through Fo and against a concentration gradient. Isolated F1 can only break down ATP, and not synthesize it.

Where does the F1 subunit of ATP synthase get its energy to catalyze the synthesis of ATP?

The function of ATP synthase is to synthesize ATP from ADP and inorganic phosphate (Pi) in the F1 sector. This is possible due to energy derived from a gradient of protons which cross the inner mitochondrial membrane from the intermembrane space into the matrix through the Fo portion of the enzyme.

Does F1 subunit rotate?

F1-ATPase is a motor enzyme in which a central shaft γ subunit rotates 120° per ATP in the cylinder made of α3β3 subunits. During rotation, the chemical energy of ATP hydrolysis (ΔGATP) is converted almost entirely into mechanical work by an elusive mechanism.

Does ATP synthase rotate clockwise or counterclockwise?

When synthesizing ATP, and viewed ‘from the bottom’ (observer faces the intermembrane space looking into the mitochondrial matrix) it rotates clockwise. ATP synthase is a membrane bound enzyme with two large subunits; F0 and F1.

Does ATP synthase rotate counterclockwise?

With only rare reversals, the γ subunit rotates counter-clockwise when observed from the “bottom” (the side closest to the FO and the membrane) of the α and β pseudo-hexamer. The obvious corollary is that rotation must be in the opposite, clockwise direction, during ATP synthesis.

What are the roles of the two subunits FO and FL of ATP synthase?

Subunits α and β make a hexamer with 6 binding sites. The other F1 subunits γ, δ, and ε are a part of a rotational motor mechanism (rotor/axle). The γ subunit allows β to go through conformational changes (i.e., closed, half open, and open states) that allow for ATP to be bound and released once synthesized.

What is F1 ATPase?

F-ATPase, also known as F-Type ATPase, is an ATPase/synthase found in bacterial plasma membranes, in mitochondrial inner membranes (in oxidative phosphorylation, where it is known as Complex V), and in chloroplast thylakoid membranes.