Vol. 19, No. 9(September 2014)

F_oF₁ ATPase (also known as ATP synthase) exists in mitochondrial inner membranes and bacterial plasma membranes to synthesize ATP (adenosine triphosphate) by using electrochemical gradient of protons (H⁺) between inside and outside of the membranes. F_o is integrated in the membranes and thought to have a rotor ring that rotates horizontally. F₁ has a dome-like structure comprised of three α and three β subunits that are alternately arranged, which is anchored to the membranes to prevent rotation. Shaft-like γ subunit connects the center of the rotor ring of F_o and F₁. As protons flow down the gradient across the membranes through F_o, the rotor ring of F_o and γ rotate, and the spin force of γ against αβ complex is used to synthesize ATP molecules. In this drawing, a waterwheel (F_o) is rotated by the gradient of water (represents proton gradient), and series of three coins (which represent ATP) are generated from the 'apparatus' (αβ of F₁), which is made from six boards being attached to the front side of the waterwheel. A man in the back takes a role to transport protons to the outside of membranes to produce proton gradient.

Genes to Cells © 2014 by the Molecular Biology Society of Japan and Wiley Publishing Asia Pty Ltd