MINFLUX imaging of a bacterial molecular machine at nanometer resolution.

The resolution achievable with the established super-resolution fluorescence nanoscopy methods, such as STORM or STED, is in general not sufficient to resolve protein complexes or even individual proteins. Recently, minimal photon flux (MINFLUX) nanoscopy has been introduced that combines the strengths of STED and STORM nanoscopy and can achieve a localization precision of less than 5 nm. We established a generally applicable workflow for MINFLUX imaging and applied it for the first time to a bacterial molecular machine, i.e., the injectisome of the enteropathogen. We demonstrate with a pore protein of the injectisome that MINFLUX can achieve a resolution down to the single molecule level. By imaging a sorting platform protein using 3D-MINFLUX, insights into the precise localization and distribution of an injectisome component in a bacterial cell could be accomplished. MINFLUX nanoscopy has the potential to revolutionize super-resolution imaging of dynamic molecular processes in bacteria and eukaryotes.