title: Structural and Functional Studies of NirC from Salmonella typhimurium.
abstract: NirC is a pentameric transport system for monovalent anions that is expressed in the context of assimilatory nitrite reductase NirBD in a wide variety of enterobacterial species. A NirC pentamer contains individual pores in each protomer that mediate the passage of at least the nitrite [Formula: see text] and nitrate [Formula: see text] anions. As a member of the formate/nitrite transporter family of membrane transport proteins, NirC shares a range of structural and functional features with the formate channel FocA and the hydrosulfide channel AsrD (HSC). NirC from the enteropathogen Salmonella typhimurium has been studied by X-ray crystallography, proton uptake assays, and different electrophysiological techniques, and the picture that has emerged shows a fast and versatile transport system for nitrite that doubles as a defense system during the enteric life of the bacterium. Structural and functional assays are described, which shed light on the transport mechanism of this important molecular machine.
authors: Department of Biophysical Chemistry, Max Planck Institute of Biophysics, Frankfurt am Main, Germany. Electronic address: rycovska@biophys.mpg.de.
authors: Adriana
authors: A
authors: Rycovska-Blume
authors: Institute for Biochemistry, Albert-Ludwigs-University Freiburg, Freiburg im Breisgau, Germany.
authors: Wei
authors: W
authors: Lü
authors: Institute for Biochemistry, Albert-Ludwigs-University Freiburg, Freiburg im Breisgau, Germany; BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Freiburg im Breisgau, Germany.
authors: Susana
authors: S
authors: Andrade
authors: Department of Biophysical Chemistry, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
authors: Klaus
authors: K
authors: Fendler
authors: Institute for Biochemistry, Albert-Ludwigs-University Freiburg, Freiburg im Breisgau, Germany; BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Freiburg im Breisgau, Germany.
authors: Oliver
authors: O
authors: Einsle
mesh_terms: D027321:Anion Transport Proteins / Q000737:chemistry* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D018360:Crystallography, X-Ray / Q000379:methods; D006801:Humans; D008958:Models, Molecular; D011487:Protein Conformation; D012480:Salmonella Infections / Q000382:microbiology; D012486:Salmonella typhimurium / Q000737:chemistry* / Q000378:metabolism
chemical_list: D027321:Anion Transport Proteins; D001426:Bacterial Proteins; C088104:NirC protein, Bacteria
keywords: Acridine orange; Crystal structure; Dequenching assay; Nitrite channel; Planar lipid bilayer; Solid-supported membrane; Transport mechanism