Interacting Bacteria Surfaces

Raviv, Uri

doi:10.1016/j.bpj.2018.03.010

Cited by 1 publication

(1 citation statement)

References 15 publications

(22 reference statements)

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“…Interestingly, for the higher increment of electrostatic screening (Dk À1 z 13 Å upon addition of 100 mM monovalent salt), only a small change in the isotherm is observed, whereas with a minor screening increment (Dk À1 z 1 Å upon further addition of 20 mM calcium ions), the range of the intermolecular repulsion is drastically reduced. This apparent mismatch clearly suggests that the influence of Ca 2þ goes beyond generic electrostatic screening, and it has to be attributed to ion-specific bridging with negatively charged phosphate and carboxylate groups (43). This is in agreement with the results of Jeworrek et al (21) for R-form LPS, where the binding of calcium to phosphate and carboxylate induces a smaller lateral domain size and drives the upright orientation of the sugar moieties.…”

Section: Lps Layers At Air-water Interfacessupporting

confidence: 87%

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

Micciulla

Gerelli

Schneck

2019

Biophysical Journal

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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 endgrafted polymer brushes. The monolayers exhibit a significant structural response to divalent cations, which goes beyond generic electrostatic screening.

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Section: Lps Layers At Air-water Interfacessupporting

confidence: 87%