Fig. 3: Conformation-specific membrane deformations mediated by the solitary ECF module.

a Cryo-EM map of the wild-type solitary ECF module with open ATPases embedded in a lipid nanodisc viewed as in Fig. 1a–c from the membrane plane onto the docking site of FolT2 (left panel) or rotated by 90° (right panel). b Cryo-EM map of the mutant solitary ECF module 2EQ_cryo with closed ATPases embedded in a lipid nanodisc from the same viewpoints as in a. The approximate nanodisc thickness is indicated with black arrows in various regions determined using Chimera X⁶⁸. The nanodisc densities (grey) were obtained from an unsharpened map lowpass filtered to 6 Å and contoured at 6.5 σ. Coarse-grained MD snapshots of both wild-type (a) and mutant (b) solitary ECF modules inserted in a bacterial model membrane (POPE: POPG: cardiolipin) from the same viewpoints as the cryo-EM maps (second panels from left and right). Lipid tails are coloured in white and lipid phosphodiester beads in green. Middle panels show membrane thickness maps around both wild-type (a) and mutant (b) solitary ECF modules. Outline represents the boundaries of the EcfT subunit with the region of transmembrane domain filled in grey. For each leaflet, lipid glycerol beads were mapped onto a xy grid, and the average grid cell lipid position determined. Membrane thickness was defined as the average z-distance between the corresponding pair of top and bottom leaflet grid cells. The individual subunits/regions are coloured as in Fig. 1.