Extended Data Fig. 3: DmSERINC purification and EM.
From: A bipartite structural organization defines the SERINC family of HIV-1 restriction factors
a, Left, chromatography profile of DmSERINC on a Superdex 200 column; the blue arrow highlights elution of the material, which was re-injected onto the column. Right, elution profile of hexameric DmSERINC. b, Left, SDS-PAGE analysis of chromatography fractions. Right, purified hexamer (first four lanes) and monomer (last four lanes) uncleaved vs cleaved sample showing higher oligomeric states in hexamer sample shift upon cleavage of the C-terminal TwinStrep tag (uncropped gel images are shown in the Source Data). c, Sample micrograph of negatively stained DmSERINC sample from 9.8-ml peak. d, 2D class averages of negatively stained DmSERINC. e, Schematic of image processing and 3D reconstruction of the DmSERINC hexamer. Volumes are shown at two contour levels, toward the protein level in solid white and the outline of the detergent micelle in transparent gray. Details of the image processing and reconstruction are given in Extended Methods. f, Left, Gold standard FSC curve for the refined DmSERINC cryo-EM map. f, Right, Euler angle distribution plot for aligned particles contributing to the 3D reconstruction; bar lengths and color (blue, low; red, high) correspond to numbers of particles in corresponding orientations. g, Cryo-EM map colored according to local resolution estimated with blocres and shown at high (left) and low (right) contour levels. h, Cryo-EM maps of the asymmetrical DmSERINC hexamer (corresponding to 3D classes 3 and 8 in Extended Data Fig. 3e) with fitted model: viewed down six-fold axis (top) or from the side (bottom). The map is contoured to highlight the protein components (right) or the detergent micelle (left).
