Cryo-EM reveals distinct conformations of E. coli ATP synthase on exposure to ATP
Meghna Sobti,
Robert Ishmukhametov,
James C Bouwer,
Anita Ayer,
Cacang Suarna,
Nicola J Smith,
Mary Christie,
Roland Stocker,
Thomas M Duncan,
Alastair G Stewart
Affiliations
Meghna Sobti
Molecular, Structural and Computational Biology Division, The Victor Chang Cardiac Research Institute, Darlinghurst, Australia; St Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, Australia
Robert Ishmukhametov
Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, United Kingdom
James C Bouwer
Molecular Horizons, The University of Wollongong, Wollongong, Australia
Anita Ayer
St Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, Australia; Vascular Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, Australia
Cacang Suarna
Vascular Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, Australia
Nicola J Smith
St Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, Australia; Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, Australia
Mary Christie
Molecular, Structural and Computational Biology Division, The Victor Chang Cardiac Research Institute, Darlinghurst, Australia; St Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, Australia
Roland Stocker
St Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, Australia; Vascular Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, Australia
Thomas M Duncan
Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
Molecular, Structural and Computational Biology Division, The Victor Chang Cardiac Research Institute, Darlinghurst, Australia; St Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, Australia
ATP synthase produces the majority of cellular energy in most cells. We have previously reported cryo-EM maps of autoinhibited E. coli ATP synthase imaged without addition of nucleotide (Sobti et al. 2016), indicating that the subunit ε engages the α, β and γ subunits to lock the enzyme and prevent functional rotation. Here we present multiple cryo-EM reconstructions of the enzyme frozen after the addition of MgATP to identify the changes that occur when this ε inhibition is removed. The maps generated show that, after exposure to MgATP, E. coli ATP synthase adopts a different conformation with a catalytic subunit changing conformation substantially and the ε C-terminal domain transitioning via an intermediate ‘half-up’ state to a condensed ‘down’ state. This work provides direct evidence for unique conformational states that occur in E. coli ATP synthase when ATP binding prevents the ε C-terminal domain from entering the inhibitory ‘up’ state.
