Binding of Cholera Toxin B-Subunit to a Ganglioside GM1-Functionalized PEG-Tethered Lipid Membrane
Year: 2022
Journal: Langmuir, Volume 38, JUN 7, page 6959–6966
Authors: Watkins, Erik B.; Dennison, Andrew J. C.; Majewski, Jaroslaw
Organizations: NSF
We report neutron reflectometry (NR) studies of polyethylene glycol (PEG)-tethered model lipid membranes at the solid-liquid interface and of cholera toxin's B-subunit(CTxB) binding to tethered membranes containing ganglioside GM1 receptors. First,tethered polymer brushes were formed by grafting silane-functionalized PEG lipopolymers toquartz from solution. Subsequent deposition of lipids by Langmuir-Blodgett/Langmuir-Schaefer (LB/LS) resulted in a tethered bilayer structure separated from the solid support bya hydrated PEG layer. NR revealed that the tethers formed a highly hydrated polymer brush,uniformly separating the bilayer from the underlying solid substrate. Further, the lipid bilayerdid not significantly perturb the brush's conformation relative to a free brush. Biological functionality of the tethered bilayers wasverified by interacting CTxB, with ganglioside GM1 receptors incorporated into the bilayer. The surface coverage of CTxB bound tothe lipid membrane,theta CTB= 0.58 +/- 0.08, was consistent with the coverage predicted for random sequential absorption, and toxinbinding did not impact the membrane conformation.
