title: Structural and Functional Characterization of the LPS Transporter LptDE from Gram-Negative Pathogens.
abstract: Incorporation of lipopolysaccharide (LPS) into the outer membrane of Gram-negative bacteria is essential for viability, and is accomplished by a two-protein complex called LptDE. We solved crystal structures of the core LptDE complexes from Yersinia pestis, Klebsiella pneumoniae, Pseudomonas aeruginosa, and a full-length structure of the K. pneumoniae LptDE complex. Our structures adopt the same plug and 26-strand β-barrel architecture found recently for the Shigella flexneri and Salmonella typhimurium LptDE structures, illustrating a conserved fold across the family. A comparison of the only two full-length structures, SfLptDE and our KpLptDE, reveals a 21° rotation of the LptD N-terminal domain that may impart flexibility on the trans-envelope LptCAD scaffold. Utilizing mutagenesis coupled to an in vivo functional assay and molecular dynamics simulations, we demonstrate the critical role of Pro231 and Pro246 in the function of the LptD lateral gate that allows partitioning of LPS into the outer membrane.
authors.affiliation: Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Istvan
authors.initials: I
authors.lastname: Botos
authors.affiliation: Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Nadim
authors.initials: N
authors.lastname: Majdalani
authors.affiliation: Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Mayclin
authors.affiliation: Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Jennifer Gehret
authors.initials: JG
authors.lastname: McCarthy
authors.affiliation: School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors.forename: Karl
authors.initials: K
authors.lastname: Lundquist
authors.affiliation: National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD 20892 USA.
authors.forename: Damian
authors.initials: D
authors.lastname: Wojtowicz
authors.affiliation: Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Travis J
authors.initials: TJ
authors.lastname: Barnard
authors.affiliation: School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors.forename: James C
authors.initials: JC
authors.lastname: Gumbart
authors.affiliation: Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Susan K
authors.initials: SK
authors.lastname: Buchanan
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000378:metabolism*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D006090:Gram-Negative Bacteria / Q000737:chemistry / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000378:metabolism*; D008958:Models, Molecular; D011485:Protein Binding; D000072417:Protein Domains; D017433:Protein Structure, Secondary
chemical_list: D001425:Bacterial Outer Membrane Proteins; D008070:Lipopolysaccharides