ATP synthase structure and mechanism

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An ATP synthase is a general term for an enzyme that can synthesize adenosine triphosphate (ATP) from adenosine diphosphate (ADP) and inorganic phosphate by utilizing some form of energy. The overall reaction sequence is: ADP + Pi â†’ ATP Molecular model of ATP synthase by X-ray diffraction method ATP synthase in E. coliThese enzymes are of crucial importance in almost all organisms, because ATP is the common "energy currency" of cells. In mitochondria, the F1FO ATP synthase has a long history of scientific study. The F1 portion of the ATP synthase is above the membrane, the FO portion is within the membrane. It's easy to visualize the FOF1 particle as resembling the fruiting body of a common mushroom, with the head being the F1 particle, the stalk being the gamma subunit of F1, and the base and "roots" being the FO particle embedded in the membrane. The F1 particle was first isolated by Ephraim Racker in 1961. The nomenclature of the enzyme suffers from a long history. The F1 fraction derives it name from the term "Fraction 1" and FO (written as a subscript "O", not "zero") derives it name from being the oligomycine binding fraction. Taking as an example the nomenclature of subunits in the bovine enzyme, many subunits have Greek and Roman alphabet names (alpha, beta, gamma, delta, epsilon and a, b, c, d, e, f, g, h), while others have more complex names such as F6 (from "Fraction 6"), OSCP (the oligomycin sensitivity conferral protein), A6L (named for the gene that codes for it in the mitochondrial genome) and IF1 (inhibitory factor 1). The F1 particle is large and can be seen in the transmission electron microscope by negative staining (1962, Fernandez-Moran et al., Journal of Molecular Biology, Vol 22, p 63). These are particles of 9 nm diameter that pepper the inner mitochondrial membrane. They were originally called elementary particles and were thought to contain the entire respiratory apparatus of the mitochondrion, but through a long series of experiments, Ephraim Racker and his colleagues were able to show that this particle is correlated with ATPase activity in uncoupled mitochondria and with the ATPase activity in submitochondrial particles created by exposing mitochondria to ultrasound. This ATPase activity was further associated with the creation of ATP by yet another long series of experiments in many laboratories. The antibiotic oligomycin inhibits ATP synthase. Text Reff: http://en.wikipedia.org/wiki/ATP_synthase (less)

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