2hqd

Conformation of the AcrB Multidrug Efflux Pump in Mutants of the Putative Proton Relay Pathway

spinqualitylabelsall models 2hqd, resolution 3.65Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2hqd is a 1 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.65Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ACRB_ECOLI AcrAB is a drug efflux protein with a broad substrate specificity. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed We previously reported the X-ray structures of wild-type Escherichia coli AcrB, a proton motive force-dependent multidrug efflux pump, and its N109A mutant. These structures presumably reflect the resting state of AcrB, which can bind drugs. After ligand binding, a proton may bind to an acidic residue(s) in the transmembrane domain, i.e., Asp407 or Asp408, within the putative network of electrostatically interacting residues, which also include Lys940 and Thr978, and this may initiate a series of conformational changes that result in drug expulsion. Herein we report the X-ray structures of four AcrB mutants, the D407A, D408A, K940A, and T978A mutants, in which the structure of this tight electrostatic network is expected to become disrupted. These mutant proteins revealed remarkably similar conformations, which show striking differences from the previously known conformations of the wild-type protein. For example, the loop containing Phe386 and Phe388, which play a major role in the initial binding of substrates in the central cavity, becomes prominently extended into the center of the cavity, such that binding of large substrate molecules may become difficult. We believe that this new conformation may mimic, at least partially, one of the transient conformations of the transporter during the transport cycle. Conformation of the AcrB multidrug efflux pump in mutants of the putative proton relay pathway.,Su CC, Li M, Gu R, Takatsuka Y, McDermott G, Nikaido H, Yu EW J Bacteriol. 2006 Oct;188(20):7290-6. PMID:17015668 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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