title: Determination of real-time efflux phenotypes in Escherichia coli AcrB binding pocket phenylalanine mutants using a 1,2'-dinaphthylamine efflux assay.
abstract: To evaluate the importance of phenylalanine residues for substrate transport in the Escherichia coli efflux pump protein AcrB, we subjected Phe-to-Ala binding pocket mutants to a real-time efflux assay with the novel near-infrared lipophilic membrane probe 1,2'-dinaphthylamine (1,2'-DNA). All mutations, with the exception of F617A, led to considerable retardation of efflux. F610A was the point mutation with the most pronounced impact, followed by F628A, F615A, F136A, and F178A. This is the first study to demonstrate the importance of single phenylalanine residues within the AcrB binding pocket for real-time substrate transport.
authors.affiliation: Department of Medicine, Center for Infectious Diseases and Travel Medicine, Albert-Ludwigs-University, University Hospital, Freiburg, Germany. juergen@bohnert.name
authors.forename: Jürgen A
authors.initials: JA
authors.lastname: Bohnert
authors.forename: Sabine
authors.initials: S
authors.lastname: Schuster
authors.forename: Magdalena
authors.initials: M
authors.lastname: Szymaniak-Vits
authors.forename: Winfried V
authors.initials: WV
authors.lastname: Kern
mesh_terms: D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D015335:Molecular Probes; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism*; D010649:Phenylalanine / Q000235:genetics / Q000378:metabolism*; D017354:Point Mutation; D011485:Protein Binding
chemical_list: D029968:Escherichia coli Proteins; D015335:Molecular Probes; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D010649:Phenylalanine; C083496:AcrB protein, E coli