Extended Data Fig. 5: Cryo-ET analysis.

a, b, f, g, Electron micrographs on the left show one tomographic slice of each sample. The density maps below obtained by subtomogram averaging are bandpass-filtered to the Fourier pixel value at 0.143 of the FSC curve. The masked FSC curves of each subtomogram average are indicated with resolutions obtained at 0.5 and 0.143 FSC. a, Mgm1 on the outside of a galactocerebroside-containing lipid tube in the apo form. On the right, a larger box size was used for processing in order to visualize the complete protein coat decorating the lipid tube. b, Mgm1 in the GTPγS-bound form on the outside of galactocerebroside-containing lipid tubes are very similar to the apo form, whereas nucleotide-free dynamin assembles differently compared to the guanosine-5′-[(β,γ)-methyleno]triphosphate-bound form²². c, GTPase assays of Mgm1 in the presence of lipid tubes containing galactocerebroside, n = 4, errors represent s.d. from the mean. d, Low-resolution cryo-ET reconstructions of GTPγS-bound Mgm1 assembled on the outside of Folch membrane tubes of different diameters, as measured between bilayer centres. On the basis of the pitch angle θ and the tube diameter d, the number of helical repeats (n-start) was estimated as n = 2πrtanθ/h, where the filament radius r = d/2+4 nm and the width from paddle tip to tip h is 13 nm. Although the basic filament architecture appears very similar, the filaments adapt their orientation to the curvature of the membrane tube. e, Representative electron micrographs showing Mgm1 coating the inner surface of a membrane tube (top) or both sides of the membrane tube (below). f, g, Cryo-ET reconstruction of Mgm1 in the apo and GTPγS-bound form on the inside of tubulated Folch liposomes, as in a and b. Grey scale bars, 10 nm; black scale bars, 100 nm.

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