title: Observing membrane protein diffusion at subnanometer resolution.
abstract: Single sodium-driven rotors from a bacterial ATP synthase were embedded into a lipid membrane and observed in buffer solution at subnanometer resolution using atomic force microscopy (AFM). Time-lapse AFM topographs show the movement of single proteins within the membrane. Subsequent analysis of their individual trajectories, in consideration of the environment surrounding the moving protein, allow principal modes of the protein motion to be distinguished. Within one trajectory, individual proteins can undergo movements assigned to free as well as to obstacled diffusion. The diffusion constants of these two modes of motion are considerably different. Without the structural information about the membrane environment restricting the moving proteins, it would not be possible to reveal insight into these mechanisms. The high-resolution AFM topographs suggest that, in future studies, such data revealed under various physiological conditions will provide novel insights into molecular mechanisms that drive membrane protein assembly and supply excellent boundary conditions to model protein-protein arrangements.
authors.affiliation: Max-Planck-Institute of Molecular Cell Biology and Genetics, Biotechnology Center, Pfotenhauerstr. 108, 01307, Dresden, Germany. mueller@mpi-cbg.de
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Müller
authors.forename: Andreas
authors.initials: A
authors.lastname: Engel
authors.forename: Ulrich
authors.initials: U
authors.lastname: Matthey
authors.forename: Thomas
authors.initials: T
authors.lastname: Meier
authors.forename: Peter
authors.initials: P
authors.lastname: Dimroth
authors.forename: Kitaru
authors.initials: K
authors.lastname: Suda
mesh_terms: D004058:Diffusion; D008565:Membrane Proteins / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D036103:Nanotechnology
chemical_list: D008565:Membrane Proteins