Two-dimensional crystallization of intact F-ATP synthase isolated from bovine heart mitochondria.

Mitochondrial F-ATP synthase produces the majority of ATP for cellular functions requiring free energy. The structural basis for proton motive force-driven rotational catalysis of ATP formation in the holoenzyme remains to be determined. Here, the purification and two-dimensional crystallization of bovine heart mitochondrial F-ATP synthase are reported. Two-dimensional crystals of up to 1 µm in size were grown by dialysis-mediated detergent removal from a mixture of decylmaltoside-solubilized 1,2-dimyristoyl-sn-glycero-3-phosphocholine and F-ATP synthase against a detergent-free buffer. A projection map calculated from an electron micrograph of a negatively stained two-dimensional crystal revealed unit-cell parameters of a = 185.0, b = 170.3 Å, γ = 92.5°.