CryoEM reconstruction of the C. thermophilum Vps1 helical assembly bound to GMPPCP and comparison with dynamin 1 ΔPRD bound to GMPPCP and PS. (A) Effects of nucleotide binding on assembly of purified Vps1. EM projection images of negatively stained Vps. Bars, 100 nm. (B) CryoEM density map of Vps1 bound to GMPPCP at 10.97 Å resolution and shown at a contour level of 1.82 σ. (C and D) Comparison of cross sections through the Vps1 (gray) and dynamin 1 ΔPRD (blue; contoured at 1.38 σ) assemblies. Slices parallel to the helical axis at the widest point of the helix were taken. (E and F) Comparison of the helical parameters of Vps1 and dynamin 1 ΔPRD. The angles subtended by the pairs of red and blue lines illustrate the angles of the GTPases and BSEs to a plane perpendicular to the helical axis, respectively. (G and H) End-on views of the Vps1 and dynamin 1 ΔPRD helices.