Particle fusion of Single Molecule Localization Microscopy data reveals dimer structure of Nup96 in Nuclear Pore Complex

Abstract

Single molecule localization microscopy offers nowadays resolution nearly down to the molecular level with specific molecular labelling, thereby being a promising tool for structural biology. In practice, however, the actual value to this field is limited primarily by incomplete fluorescent labeling of the structure. This missing information can be completed by merging information from many structurally identical particles equivalent to cryo-EM single-particle analysis. In this analysis, we present particle averaging of fluorescently labelled Nup96 in the Nuclear Pore Complex followed by data analysis to show that Nup96 occurs as a dimer with in total 32 copies per pore. We use Artificial Intelligence assisted modeling in Alphafold to extend the existing cryo-EM model of Nup96 to accurately pinpoint the positions of the fluorescent labels and show the accuracy of the match between fluorescent and cryo-EM data to be better than 3 nm in-plane and 5 nm out-of-plane.