title: Lipopolysaccharide transport to the cell surface: biosynthesis and extraction from the inner membrane.
abstract: The cell surface of most Gram-negative bacteria is covered with lipopolysaccharide (LPS). The network of charges and sugars provided by the dense packing of LPS molecules in the outer leaflet of the outer membrane interferes with the entry of hydrophobic compounds into the cell, including many antibiotics. In addition, LPS can be recognized by the immune system and plays a crucial role in many interactions between bacteria and their animal hosts. LPS is synthesized in the inner membrane of Gram-negative bacteria, so it must be transported across their cell envelope to assemble at the cell surface. Over the past two decades, much of the research on LPS biogenesis has focused on the discovery and understanding of Lpt, a multi-protein complex that spans the cell envelope and functions to transport LPS from the inner membrane to the outer membrane. This paper focuses on the early steps of the transport of LPS by the Lpt machinery: the extraction of LPS from the inner membrane. The accompanying paper (May JM, Sherman DJ, Simpson BW, Ruiz N, Kahne D. 2015 Phil. Trans. R. Soc. B 370, 20150027. (doi:10.1098/rstb.2015.0027)) describes the subsequent steps as LPS travels through the periplasm and the outer membrane to its final destination at the cell surface.
authors.affiliation: Department of Microbiology, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
authors.forename: Brent W
authors.initials: BW
authors.lastname: Simpson
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA.
authors.forename: Janine M
authors.initials: JM
authors.lastname: May
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Sherman
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA Department of Molecular and Cellular Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA kahne@chemistry.harvard.edu.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kahne
authors.affiliation: Department of Microbiology, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA ruiz.82@osu.edu.
authors.forename: Natividad
authors.initials: N
authors.lastname: Ruiz
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D001693:Biological Transport, Active; D002462:Cell Membrane / Q000378:metabolism*; D004734:Energy Metabolism; D006090:Gram-Negative Bacteria / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000096:biosynthesis / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D008954:Models, Biological; D008958:Models, Molecular; D049294:Phospholipid Transfer Proteins / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D008070:Lipopolysaccharides; D008565:Membrane Proteins; C079726:MsbA protein, Bacteria; D049294:Phospholipid Transfer Proteins
keywords: glycolipid; lpx; membrane biogenesis; permeability barrier