Drug Export Pathway of Multidrug Exporter AcrB Revealed by DARPin Inhibitors
Figure 4
The Extension of the Channels in the Individual Subunits of AcrB
The view is the same as in Figure 2A. For simplicity, the DARPins are not shown. The channels are colored in transparent blue. The potential export pathway is represented by dashed lines. The loop forming the bottom of the periplasmic channel entrance (PE) and TM helix 8 are highlighted in red. The gate to the central funnel formed by the residues Gln124, Gln125, and Tyr758 is shown in space filling representation for clarity.
(A) In subunit A, the channel is opened to the periplasm, while the gate is in the closed conformation. The pore domain subdomains are labeled.
(B) In subunit B, the channel displays an open conformation to the periplasm and to the membrane bilayer (CE). The gate is in a closed conformation.
(C) Subunit C displays a closed conformation of the channel entrances, while the gate is open, extending the channel to the central funnel.