Structure of the ATP‐synthase studied by electron microscopy and image processing

The structure of ATP synthase from beef heart mitochondria has been studied by electron microscopy and image processing using negatively stained specimens of detergent-solubilized and membrane-bound molecules. The F1-ATPase and the membrane-embedded F0 sector of ATP synthase are found to be connected by a narrow stalk, 4-4.5 nm long and 3-3.5 nm wide, projecting about 4.2 nm from the membrane surface. The F0 sector has a globular shape, 6-8 nm in diameter and, in part, extends from the membrane lipid bilayer.