Nonequilibrium fluctuations of lipid membranes by the rotating motor protein F 1 F 0 -ATP synthase

Víctor Almendro-Vedia , Paolo Natale , Michael Mell , Stéphanie Bonneau (1) , Francisco Monroy , Frédéric Joubert (2) , Iván López-Montero

1 LJP - Laboratoire Jean Perrin
2 Signalisation et physiopathologie cardiaque

ATP synthase is a rotating membrane protein that synthesizes ATP through proton-pumping activity across the membrane. To unveil the mechanical impact of this molecular active pump on the bending properties of its lipid environment, we have functionally reconstituted the ATP synthase in giant unilamellar vesicles and tracked the membrane fluctuations by means of flickering spectros-copy. We find that ATP synthase rotates at a frequency of about 20 Hz, promoting large nonequilibrium deformations at discrete hot spots in lipid vesicles and thus inducing an overall membrane softening. The enhanced nonequilibrium fluctuations are compatible with an accumulation of active proteins at highly curved membrane sites through a curvature−protein coupling mechanism that supports the emergence of collective effects of rotating ATP synthases in lipid membranes. giant vesicles | active membranes | mechanical properties | flickering spectroscopy | biological nanorotors

Domaines: Biophysique [physics.bio-ph]

Víctor Almendro-Vedia, Paolo Natale, Michael Mell, Stéphanie Bonneau, Francisco Monroy, et al.. Nonequilibrium fluctuations of lipid membranes by the rotating motor protein F 1 F 0 -ATP synthase. Proceedings of the National Academy of Sciences of the United States of America, 2017, 114 (43), pp.11291 - 11296. ⟨10.1073/pnas.1701207114⟩. ⟨hal-01646349⟩