Electron microscopy of two-dimensional crystals of mitochondrial ATP synthase

Two-dimensional crystals of the mitochondrial ATP synthase up to 0.4 μm in size were obtained from the detergent-lipid-protein micelles by detergent dialysis. A projected map of the negatively stained crystal was calculated from electron microscopical images by the Fourier-filtering procedure at about 2.8 nm resolution. The unit cell (with not more than two ATP synthase molecules) has the following parameters: a = 13.0 nm, b = 25.6 nm and γ = 86°. Two alternative models for the crystal structural organization were suggested, viz. with one or two protein molecules per unit cell.