title: QCM-D studies of human norovirus VLPs binding to glycosphingolipids in supported lipid bilayers reveal strain-specific characteristics.
abstract: Susceptibility to norovirus infection has been linked to secretor status. Norovirus virus-like particles (VLPs; 0- 20 microg/mL) from the Norwalk (GI.1) and Dijon (GII.4) strains were assayed for binding to H type 1 and Lewis a pentaglycosylceramides, incorporated in laterally fluid supported lipid bilayers. Binding kinetics was monitored in real time in 40 microL stationary reaction chambers, using quartz crystal microbalance with dissipation (QCM-D) monitoring. Both strains displayed binding only to H type 1 and not to Lewis a glycosphingolipids, typical for epithelial cells of susceptible and resistant individuals, respectively. This binding specificity was confirmed by VLPs binding to the two glycosphingolipids chromatographed on TLC-plates. Experiments using bilayers with mixtures of H type 1 and Lewis a, with the total glycosphingolipid concentration constant at 10 wt%, showed that binding was only dependent on H type 1 concentrations and identical to experiments without additional Lewis a. Both strains showed a threshold concentration of H type 1 below which no binding was observable. The threshold was one order of magnitude higher for the Dijon strain (2 wt% versus 0.25 wt%) demonstrating that the interaction with a significantly larger number of glycosphingolipids was needed for the binding of the Dijon strain. The difference in threshold glycosphingolipid concentrations for the two strains suggests a lower affinity for the glycosphingolipid for the Dijon compared to the Norwalk strain. We propose that VLPs initially bind only a few glycosphingolipids but the binding is subsequently strengthened by lateral diffusion of additional glycosphingolipids moving into the interaction area.
authors.affiliation: Department of Clinical Chemistry and Transfusion Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Gustaf E
authors.initials: GE
authors.lastname: Rydell
authors.forename: Andreas B
authors.initials: AB
authors.lastname: Dahlin
authors.forename: Fredrik
authors.initials: F
authors.lastname: Höök
authors.forename: Göran
authors.initials: G
authors.lastname: Larson
mesh_terms: D001665:Binding Sites; D003460:Crystallization; D006028:Glycosphingolipids / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry*; D029322:Norovirus / Q000737:chemistry / Q000145:classification* / Q000378:metabolism*; D011791:Quartz
chemical_list: D006028:Glycosphingolipids; D008051:Lipid Bilayers; D011791:Quartz