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

Molecular structure of an axle-less F1-ATPase (#435)

Emily J Furlong 1 2 , Yi C Zeng 1 3 , Simon HJ Brown 4 , Meghna Sobti 1 3 , Alastair G Stewart 1 3
  1. Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
  2. Research School of Biology, Australian National University, Canberra, ACT, Australia
  3. St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
  4. School of Chemistry and Molecular Bioscience, Molecular Horizons, and ARC Centre for Cryo-electron Microscopy of Membrane Proteins, University of Wollongong, Wollongong, NSW, Australia

F1Fo ATP synthase is a molecular rotary motor that can generate ATP using a transmembrane proton motive force. Isolated F1-ATPase catalytic cores can hydrolyse ATP, passing through a series of conformational states involving rotation of the central γ rotor subunit and the opening and closing of the catalytic β subunits. Cooperativity in F1-ATPase has long thought to be conferred through the γ subunit, with three key interaction sites between the γ and β subunits being identified. Single molecule studies have demonstrated that the F1 complexes lacking the γ axle still “rotate” and hydrolyse ATP, but with less efficiency. We solved the cryogenic electron microscopy structure of an axle-less Bacillus sp. PS3 F1-ATPase. The structure suggests why the full-length axle is required for efficient ATP hydrolysis by F1-ATPase.