Extended Data Fig. 1: Electron cryo-microscopy of the CsgG:CsgF complex.
From: A dual-constriction biological nanopore resolves homonucleotide sequences with high fidelity
a, SDS PAGE of CsgG or CsgG:CsgF complex obtained by tandem affinity purification of the outer membrane proteins extracted from cells expressing CsgG-Strep II (pPG1) or CsgG-Strep II and CsgF-His (pNA62), respectively. Gel representative for n>10 experiments. b, Representative 2D class averages for the CsgG:CsgF dataset enriched for single pores (that is C9 CsgG:CsgF complexes), generated using SIMPLE and used for 3D reconstruction using Relion-2.0. c, Off-axis top view and cross-sectional side view of the CsgG:CsgF cryo-EM 3D electron potential map reconstructed to 3.4 Å. d, Representative region of electron potential map of the CsgG:CsgF complex. Region of focus is the constriction helix of FCP, stacking against the lumen of the CsgG β-barrel. One CsgF protomer is highlighted in purple, the others in grey; CsgG is depicted in gold. Heteroatoms are in blue (nitrogens) and red (oxygens). The electron potential map is cut-off at a contour of 0.5, shown in stick and mesh representation, rendered using UCSF Chimera 1.10.2. (e) Fourier Shell Correlation (FSC) curves of the final 3D reconstruction (black: FSC corrected map, green: FSC unmasked map, blue: FSC masked map, red: FSC phase randomized unmasked map).
