Figure 2.
Organization and Interactions of Lipids in the Central Cavity of AcrB
(A) Left panel shows a view along the central axis of the AcrBZ complex from the cytoplasmic side, with E. coli lipids at natural abundance. Right panel shows the cryo-EM density in the central region, which reveals the hexagonal pattern for the lipids. Colors of AcrB subunits and AcrZ are the same as in Figure 1.
(B) Snapshots of the lipid bilayer in the central cavity of AcrB at the end of a 500-ns simulation.
(C) Average order parameters (Scd) of the palmitic (P) and vaccenic (V) acid lipid tails of PVPE (1-palmitoyl 2-cis-vaccenic phosphatidylethanolamine) in the outer and inner leaflets of the central cavity in two simulations (Sim1 and Sim2).
(D) Hydrophobic residues that protrude into the outer leaflet of the lipid bilayer during the simulations in the different AcrB protomers, viewed perpendicular to the plane of the membrane (L, navy blue; T, blue; and O, cyan blue).