Distinct dissociation rates of murine and human norovirus P-domain dimers suggest a role of dimer stability in virus-host interactions
Robert Creutznacher, Thorben Maaß, Jasmin Dülfer, Clara Feldmann, Veronika Hartmann, Miranda Sophie Lane, Jan Knickmann, Leon Torben Westermann, Lars Thiede, Thomas J. Smith, Charlotte Uetrecht, Álvaro Mallagaray, Christopher A. Waudby, Stefan Taube, Thomas Peters
Abstract
Abstract Norovirus capsids are icosahedral particles composed of 90 dimers of the major capsid protein VP1. The C-terminus of the VP1 proteins forms a protruding (P)-domain, mediating receptor attachment, and providing a target for neutralizing antibodies. NMR and native mass spectrometry directly detect P-domain monomers in solution for murine (MNV) but not for human norovirus (HuNoV). We report that the binding of glycochenodeoxycholic acid (GCDCA) stabilizes MNV-1 P-domain dimers (P-dimers) and induces long-range NMR chemical shift perturbations (CSPs) within loops involved in antibody and receptor binding, likely reflecting corresponding conformational changes. Global line shape analysis of monomer and dimer cross-peaks in concentration-dependent methyl TROSY NMR spectra yields a dissociation rate constant k off of about 1 s −1 for MNV-1 P-dimers. For structurally closely related HuNoV GII.4 Saga P-dimers a value of about 10 −6 s −1 is obtained from ion-exchange chromatography, suggesting essential differences in the role of GCDCA as a cofactor for MNV and HuNoV infection.