Contact
    Start Publications Structure and Conformation of Wild-Type Bacterial ...
    ←  Publication Finder
    KSV NIMA

    Structure and Conformation of Wild-Type Bacterial Lipopolysaccharide Layers at Air-Water Interfaces

    Year: 2019

    Journal: Biophys. J., Volume 116, 1-Apr, page 1259–1269

    Authors: Micciulla, Samantha; Gerelli, Yuri; Schneck, Emanuel

    Organizations: Max Planck SocietyMax Planck Society; German Federal Ministry of Research and Education within the Rontgen-Angstrom cluster (grant 3PhaseNR) [05K16ECA]; Emmy-Noether grant of the German Research Foundation [SCHN 1396/1]

    The outer membrane of Gram-negative bacteria is of great scientific interest because it mediates the action of antimicrobial agents. The membrane surface is composed of lipopolysaccharide (LPS) molecules with negatively charged oligosaccharide headgroups. To a certain fraction, LPSs additionally display linear polysaccharides termed O-side chains (OSCs). Structural studies on bacterial outer surfaces models, based on LPS monolayers at air-water interfaces, have so far dealt only with rough mutant LPSs lacking these OSCs. Here, we characterize monolayers of wild-type LPS from Escherichia coli O55:B5 featuring strain-specific OSCs in the presence of defined concentrations of monovalent and divalent ions. Pressure-area isotherms yield insight into in-plane molecular interactions and monolayer elastic moduli. Structural investigations by x-ray and neutron reflectometry reveal the saccharide conformation and allow quantifying the area per molecule and the fraction of LPS molecules carrying OSCs. The OSC conformation is satisfactorily described by the self-consistent field theory for end-grafted polymer brushes. The monolayers exhibit a significant structural response to divalent cations, which goes beyond generic electrostatic screening.
    View publication