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The AcrA/AcrB/TolC complex spans the inner and outer membranes of Escherichia coli and serves as its major drug-resistance pump. Driven by the proton motive force, it mediates the efflux of bile salts, detergents, organic solvents, and many structurally unrelated antibiotics. Here, we report a crystallographic structure of trimeric AcrB determined at 2.9(More)
AcrAB-TolC is the major efflux protein complex in Escherichia coli extruding a vast variety of antimicrobial agents from the cell. The inner membrane component AcrB is a homotrimer, and it has been postulated that the monomers cycle consecutively through three conformational stages designated loose (L), tight (T), and open (O) in a concerted fashion.(More)
Under anoxic conditions in the presence of an oxidizable cosubstrate such as glucose or glycerol, Escherichia coli converts citrate to acetate and succinate. Two enzymes are specifically required for the fermentation of the tricarboxylic acid, i.e., a citrate uptake system and citrate lyase. Here we report that the open reading frame (designated citT)(More)
Membrane transporters of the RND superfamily confer multidrug resistance to pathogenic bacteria, and are essential for cholesterol metabolism and embryonic development in humans. We use high-resolution X-ray crystallography and computational methods to delineate the mechanism of the homotrimeric RND-type proton/drug antiporter AcrB, the active component of(More)
The AcrA-AcrB-TolC complex is the major multidrug efflux pump in Escherichia coli. The asymmetric structure of the trimeric inner-membrane component AcrB implies functional rotation of the monomers and a peristaltic mode of drug efflux. This mechanism suggests the occurrence of conformational changes in the periplasmic pore domain through the movements of(More)
Antimicrobial resistance of human pathogenic bacteria is an emerging problem for global public health. This resistance is often associated with the overproduction of membrane transport proteins that are capable to pump chemotherapeutics, antibiotics, detergents, dyes and organic solvents out of the cell. In Gram-negative bacteria such as Escherichia coli(More)
The three-component AcrA/AcrB/TolC efflux system of Escherichia coli catalyzes the proton motive force-driven extrusion of a variety of cytotoxic compounds. The inner membrane pump component AcrB belongs to the resistance nodulation and cell division (RND) superfamily and is responsible for drug specificity and energy transduction of the entire tripartite(More)
Resistance of pathogens to antibiotics is often dependent on multi-drug export proteins that reside in the inner membrane of bacteria. This work describes the expression, purification, crystallization and preliminary crystallographic analysis of AcrB of Escherichia coli. Together with AcrA and TolC, AcrB forms a proton motive force dependent efflux pump of(More)
A His-tagged derivative of the multidrug efflux pump AcrB could be crystallized in three different space groups (R3, R32 and P321). Experimental MAD-phasing maps from R32 AcrB(His) crystals were obtained to a resolution of 3.5 A. Datasets of native and substrate soaked AcrB(His) crystals were collected at the Swiss Light Source X06SA beamline up to a(More)
Co-crystallization of membrane proteins with antibody fragments may emerge as a general tool to facilitate crystal growth and improve crystal quality. The bound antibody fragment enlarges the hydrophilic part of the mostly hydrophobic membrane protein, thereby increasing the interaction area for possible protein-protein contacts in the crystal.(More)