News Archive
Nature Chemical Biology Highlight
24 October 2010. The microscopic mechanism of coupled c-ring rotation and ion translocation in F1Fo-ATP synthases is unknown. A team of scientists led by Thomas Meier and José Faraldo-Gomez presents evidence that the ability of c-rings to rotate within the Fo complex derives from the interplay between the ion-binding sites and their nonhomogenous microenvironment. The evidence the scientists published online in the journal Nature Chemical Biology (highlight) rests on three atomic structures of the c15 rotor from crystals grown at low pH, soaked at high pH and, after N,N′-dicyclohexylcarbodiimide (DCCD) modification, resolved at 1.8, 3.0 and 2.2 Å, respectively. Alongside a quantitative DCCD-labeling assay and free-energy molecular dynamics calculations, these data demonstrate how the thermodynamic stability of the so-called proton-locked state is maximized by the lipid membrane. By contrast, a hydrophilic environment at the a-subunit–c-ring interface appears to unlock the binding-site conformation and promotes proton exchange with the surrounding solution. Rotation thus occurs as c-subunits stochastically alternate between these environments, directionally biased by the electrochemical transmembrane gradient. More ...
Full reference: Pogoryelov D, Krah A, Langer JD, Yildiz O, Faraldo-Gomez JD, Meier T (2010) Microscopic rotary mechanism of ion translocation in the Fo complex of ATP synthases. Nature Chemical Biology: published online 24 October 2010.
Contact:
José Faraldo-Gómez
Tel. +49 (0) 69 6303 1500
jose.faraldo@biophys.mpg.de
Thomas Meier
Tel. +49 (0) 69 6303-3038
thomas.meier@biophys.mpg.de
Max Planck Institute of Biophysics
Max von Laue Str. 3
60438 Frankfurt am Main
Germany