Seminar of Mark Bates - Institute for Nanophotonics Göttingen, Germany

Mark Bates  

Visualizing protein complexes with single-molecule fluorescence microscopy 

Abstract: Understanding cellular function often requires knowing how proteins are arranged within macromolecular assemblies in their native cellular context. Fluorescence microscopy provides molecular specificity, but conventional imaging lacks the spatial resolution to resolve this organization in three dimensions. Single-molecule localization microscopy, including STORM, overcomes this limitation by reconstructing images from the positions of individual fluorescent probes. 

A central example is 4Pi-STORM, which uses coherent fluorescence detection with two opposing objective lenses to achieve near-isotropic 3D localization precision. By combining interferometric detection with dynamic models of the 4Pi point spread function, this approach reaches localization precisions of 2–3 nm and enables detailed imaging of protein organization in mitochondria, axons, and nuclear pore complexes.  In the nuclear pore complex, 4Pi-STORM reveals nucleoporin organization and transport pathways through individual pores, illustrating how fluorescence nanoscopy can connect molecular architecture with biological function in situ. These results highlight how super-resolution fluorescence microscopy complements electron tomography: while cryo-ET provides ultrastructural context, fluorescence nanoscopy reveals molecular identity, compositional heterogeneity, and flexible protein domains that may be inaccessible to electron microscopy or ensemble averaging.