Fig. 4: Cryo-EM structures of the plasticity-reduced Vipp1 dL10Ala.
From: Structural basis for Vipp1 membrane binding: from loose coats and carpets to ring and rod assemblies
a, Topology of the Vipp1 structure with indicated mutation site for Vipp1 dL10Ala and color-coded helices: α0, green; α1, red; α2 + α3, violet; α4, blue; α5, cyan; α6, white. b, The 2D class averages showing different Vipp1 dL10Ala structures after reconstitution with lipids. In addition to rings and stacked rings, we identified type I and type II tubes. c, Cryo-EM structures of two type II (top rows) and two type IIb assemblies (bottom rows). Left, cryo-EM maps of Vipp1 dL10Ala tubes. Center left, central xy slices of cryo-EM maps with the fitted models. Center right, atomic models of Vipp1 tubes in ribbon representation. Right, central z slices of cryo-EM maps in grayscale with highlighted unassigned density in orange. d, Radial density profiles of respective Vipp1 dL10Ala tubes (respective outer diameters of the tubes are displayed in the upper right corner of each plot). Dashed lines indicate the peaks of the inner and outer leaflet densities of the tubulated bilayer. Bottom, profile showing the superposition of type IIb (solid green) and type II (gray dashed) tubes of 270-Å diameter assigned with putative structural elements. e, Cryo-EM map of Vipp1 dL10Ala type IIb tubes with surface colored Vipp1 α-helices and enlarged view of the cryo-EM map with the fitted model showing the helix α0 interactions and putative position of a membrane outer leaflet (OL).
