The series of conformational states adopted by rotorless F1-ATPase during its hydrolysis cycle

F1Fo ATP synthase interchanges phosphate transfer energy and proton motive force via a rotary catalytic mechanism and isolated F1-ATPase subcomplexes can also hydrolyze ATP to generate rotation of their central γ rotor subunit. As ATP is hydrolyzed, the F1-ATPase cycles through a series of conformational states that mediates unidirectional rotation of the rotor. However, even in the absence of a rotor, the α and β subunits are still able to pass through a series of conformations, akin to those that generate rotation. Here, we use cryoelectron microscopy to establish the structures of these rotorless states. These structures indicate that cooperativity in this system is likely mediated by contacts between the β subunit lever domains, irrespective of the presence of the γ rotor subunit. These findings provide insight into how long-range information may be transferred in large biological systems. [Display omitted] •The structures of “rotorless” F1-ATPase under three conditions•Suggest the transitions that may occur during hydrolysis by “rotorless” F1-ATPase•Regions important for cooperativity in this system are highlighted ATP synthase is an important enzyme that generates the majority of cellular energy. Sobti et al. used structural analyses to show how a component of this enzyme can operate in its simplest form. The study highlights an important region that is likely responsible for coordinating changes within the enzyme.