Visualizing movements inE. coliF₁F_oATP synthase indicates how the F₁and F_omotors are coupled

AbstractF1FoATP synthase functions as a biological rotary generator and makes a major contribution to cellular energy production. It is comprised of two motors that are coupled together by a central “rotor” and peripheral “stator” stalk. Proton flow through the Fomotor generates rotation of the central stalk that induces conformation changes that catalyze production of ATP in the F1motor. Here we provide 3-4 Å resolution cryo-EM structures ofE. coliF1FoATP synthase in 10 mM MgADP. In addition to generating a comprehensive structural model ofE. coliF1FoATP synthase to provide a framework to interpret mutagenesis studies, we describe a rotational sub-step of the Fomotorc-ring associated with long-range conformational changes that suggests an elegant mechanism by which the F1and Fomotors can be coupled with minimal energy loss.