Fig. 1. Vps4 hexamers in open and closed conformations.

(A and B) Vps4 hexamer in the open (A) and closed (B) conformations. Top and middle: Side and top views, respectively, of cryo-EM density maps. Bottom: Top view of structural models. Difference densities (red) corresponding to ATP are shown at the same threshold cutoff. (C) Flexibly fit crystal structure of Vps4 subunit into the corresponding EM density region (subunit D, closed conformation). (D) Structural transitions between the open and closed Vps4 conformers. The conformers are aligned on the basis of subunits B to F (gray) and shown from the side of subunit A in the open (orange) and closed (yellow) conformations.