title: Type I secretion and multidrug efflux: transport through the TolC channel-tunnel.
abstract: The crystal structure of TolC from Escherichia coli was recently determined to 2.1-A resolution and shows a unique type of channel architecture: a 12-stranded beta-barrel spans the outer membrane and is attached to a long alpha-helical channel that penetrates far into the periplasm. The structure suggests a mechanism for its role in secretion of proteins and in efflux of toxic small molecules. The TolC export pathway is compared with several import pathways of gram-negative bacteria where the outer membrane protein structures are also known.
authors.affiliation: Department of Crystallography, Birkbeck College, Malet Street, WC1E 7HX, London, UK. s.buchanan@mail.cryst.bbk.ac.uk
authors.forename: S K
authors.initials: SK
authors.lastname: Buchanan
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000378:metabolism*; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins; D006090:Gram-Negative Bacteria / Q000378:metabolism*; D026901:Membrane Transport Proteins; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D011487:Protein Conformation
chemical_list: D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D004364:Pharmaceutical Preparations; C073126:tolC protein, E coli