Download MendeleyHigh-Resolution Structure of the Rotor Ring of a Proton-Dependent ATP Synthase.
Pogoryelov, D., Yildiz, O., Faraldo-Gomez, J.D., Meier, T.(2009) Nat Struct Mol Biol 16: 1068
- PubMed: 19783985
- DOI: https://doi.org/10.1038/nsmb.1678
- Primary Citation of Related Structures:
2WIE - PubMed Abstract:
The crystal structure of the c-ring from the proton-coupled F1Fo ATP synthase from Spirulina platensis is shown at 2.1-A resolution. The ring includes 15 membrane-embedded c subunits forming an hourglass-shaped assembly. The structure demonstrates that proton translocation across the membrane entails protonation of a conserved glutamate located near the membrane center in the c subunit outer helix. The proton is locked in this site by a precise hydrogen bond network reminiscent of that in Na+-dependent ATP synthases. However, the structure suggests that the different coordination chemistry of the bound proton and the smaller curvature of the outer helix drastically enhance the selectivity of the H+ site against other cations, including H3O+. We propose a model for proton translocation whereby the c subunits remain in this proton-locked state when facing the membrane lipid. Proton exchange would occur in a more hydrophilic and electrostatically distinct environment upon contact with the a subunit interface.
Organizational Affiliation:
Department of Structural Biology, Max-Planck Institute of Biophysics, Frankfurt am Main, Germany.
