In the bacterium Escherichia coli, the Min proteins oscillate between the cell poles to select the cell center as division site. This dynamic pattern has been proposed to arise by self-organization of these proteins, and several models have suggested a reaction-diffusion type mechanism. Here, we found that the Min proteins spontaneously formed planar surface waves on a flat membrane in vitro. The formation and maintenance of these patterns, which extended for hundreds of micrometers, required adenosine 5'-triphosphate (ATP), and they persisted for hours. We present a reaction-diffusion model of the MinD and MinE dynamics that accounts for our experimental observations and also captures the in vivo oscillations.

The ultimate goal of biological superresolution fluorescence microscopy is to provide threedimensional resolution at the size scale of a fluorescent marker. Here, we show that, by localizing individual switchable fluorophores with a probing doughnut-shaped excitation beam, MINFLUX nanoscopy provides 1-3 nanometer resolution in fixed and living cells. This progress has been facilitated by approaching each fluorophore iteratively with the probing doughnut minimum, making the resolution essentially uniform and isotropic over scalable fields of view. MINFLUX imaging of nuclear pore complexes of a mammalian cell shows that this true nanometer scale resolution is obtained in three dimensions and in two color channels. Relying on fewer detected photons than popular camera-based localization, MINFLUX nanoscopy is poised to open a new chapter in the imaging of protein complexes and distributions in fixed and living cells.While STED 1, 2 and PALM/STORM 3, 4 fluorescence microscopy (nanoscopy) can theoretically achieve a resolution at the size of a single fluorophore, in practice they are typically limited to about 20 nm.Owing to a synergistic combination of the specific strengths of these key superresolution concepts, the recently introduced MINFLUX nanoscopy 5 can attain a spatial resolution of about the size of a molecule, conceptually without constraints from any wavelength or numerical aperture. In MINFLUX imaging, the fluorophores are switched individually like in PALM/STORM, whereas the localization is accomplished by using a movable excitation beam featuring an intensity minimum, such as a doughnut. The minimum ideally is a zero intensity point that is targetable like a probe 6 .