title: Proteins required for lipopolysaccharide assembly in Escherichia coli form a transenvelope complex.
abstract: The viability of Gram-negative organisms is dependent on the proper placement of lipopolysaccharide (LPS) in the outer leaflet of its outer membrane. LPS is synthesized inside the cell and transported to the surface by seven essential lipopolysaccharide transport (Lpt) proteins. How these proteins cooperate to transport LPS is unknown. We show that these Lpt proteins can be found in a membrane fraction that contains inner and outer membranes and that they copurify. This constitutes the first evidence that the Lpt proteins form a transenvelope complex. We suggest that this protein bridge provides a route for LPS transport across the cell envelope.
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Shu-Sin
authors.initials: SS
authors.lastname: Chng
authors.forename: Luisa S
authors.initials: LS
authors.lastname: Gronenberg
authors.forename: Daniel
authors.initials: D
authors.lastname: Kahne
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000502:physiology; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D001692:Biological Transport; D002352:Carrier Proteins / Q000737:chemistry / Q000502:physiology; D002473:Cell Wall / Q000737:chemistry* / Q000378:metabolism* / Q000502:physiology; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000502:physiology; D046912:Multiprotein Complexes / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*
chemical_list: D018528:ATP-Binding Cassette Transporters; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D008070:Lipopolysaccharides; C532155:LptA protein, E coli; C543317:LptB protein, E coli; C543318:LptC protein, E coli; C529275:LptF protein, E coli; C529276:LptG protein, E coli; D008565:Membrane Proteins; D046912:Multiprotein Complexes; C043426:inner membrane protein, E coli
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