Fig. 4: Analysis of the lipid-binding site in AcrB.
Density map of C8-C0-50-purified AcrB seen around the transmembrane region from the side and base. The lipids from AcrB solved by cryoEM in SMA are superimposed and shown in purple, red and orange for carbon, oxygen and phosphate, respectively. The density contour level in (a) and (b) is comparable to that of Fig. 3c (0.025), a lower threshold of density (0.016) is shown in (c) and (d) with increased noise. At both contour levels, no density is present that could be assigned to the bound lipids.
