Oral Presentation 49th Lorne Conference on Protein Structure and Function 2024

 Conformational states adopted by rotorless F1-ATPase during its hydrolysis cycle (#28)

Meghna Sobti 1 , Hiroshi Ueno 2 , Simon Brown 3 , Hiroyuki Noji 2 , Alastair Stewart 1
  1. Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
  2. Applied Chemistry, Graduate School of Engineering, Univeristy of Tokyo, Tokyo, Japan
  3. Molecular Horizons, The University of Wollongong, Wollongong, NSW, Australia

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 g 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 a and b subunits are still able to pass through a series of conformations, akin to those that generate rotation. We used cryo-electron microscopy to establish the structures of these rotorless states. These structures indicate that cooperativity in this system is likely mediated by contacts between the b subunit lever domains, irrespective of the presence of the g rotor subunit. These findings provide insight into how long-range information may be transferred in large biological systems.