title: Characterization of interactions between LPS transport proteins of the Lpt system.
abstract: The lipopolysaccharide transport system (Lpt) in Gram-negative bacteria is responsible for transporting lipopolysaccharide (LPS) from the cytoplasmic surface of the inner membrane, where it is assembled, across the inner membrane, periplasm and outer membrane, to the surface where it is then inserted in the outer leaflet of the asymmetric lipid bilayer. The Lpt system consists of seven known LPS transport proteins (LptA-G) spanning from the cytoplasm to the cell surface. We have shown that the periplasmic component, LptA is able to form a stable complex with the inner membrane anchored LptC but does not interact with the outer membrane anchored LptE. This suggests that the LptC component of the LptBFGC complex may act as a dock for LptA, allowing it to bind LPS after it has been assembled at the inner membrane. That no interaction between LptA and LptE has been observed supports the theory that LptA binds LptD in the LptDE homodimeric complex at the outer membrane.
authors.affiliation: Department of Biochemistry, McGill University, Montréal, Que., Canada.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Bowyer
authors.forename: Jason
authors.initials: J
authors.lastname: Baardsnes
authors.forename: Eunice
authors.initials: E
authors.lastname: Ajamian
authors.forename: Linhua
authors.initials: L
authors.lastname: Zhang
authors.forename: Miroslaw
authors.initials: M
authors.lastname: Cygler
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D019897:Periplasm / Q000378:metabolism*; D055503:Protein Multimerization
chemical_list: D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D008070:Lipopolysaccharides; C532155:LptA protein, E coli; C543318:LptC protein, E coli; C514179:LptE protein, E coli; D008565:Membrane Proteins