We determined the structure of a complete, dimeric F1
-ATP synthase from mitochondria of the yeast Yarrowia lipolytica
by a combination of cryo-electron microscopy (cryo-EM) and X-ray crystallography. The structure resolves 58 of the 60 subunits in the dimer. Horizontal helices of subunit a
wrap around the c-ring rotor, and a total of six vertical helices assigned to subunits a, b, f, i,
span the membrane. Our data explain the structural basis of cristae formation in mitochondria, a landmark signature of eukaryotic cell morphology.