NMR Experiments Shed New Light on Glycan Recognition by Human and Murine Norovirus Capsid Proteins

Robert Creutznacher,Clara Feldmann,Stefan Taube,Patrick Ogrissek,Thorben Maass,Thomas Peters,Georg Wallmann,Hannelore Peters,Marit Lingemann,Alvaro Mallagaray

doi:10.3390/v13030416

Abstract

Glycan–protein interactions are highly specific yet transient, rendering glycans ideal recognition signals in a variety of biological processes. In human norovirus (HuNoV) infection, histo-blood group antigens (HBGAs) play an essential but poorly understood role. For murine norovirus infection (MNV), sialylated glycolipids or glycoproteins appear to be important. It has also been suggested that HuNoV capsid proteins bind to sialylated ganglioside head groups. Here, we study the binding of HBGAs and sialoglycans to HuNoV and MNV capsid proteins using NMR experiments. Surprisingly, the experiments show that none of the norovirus P-domains bind to sialoglycans. Notably, MNV P-domains do not bind to any of the glycans studied, and MNV-1 infection of cells deficient in surface sialoglycans shows no significant difference compared to cells expressing respective glycans. These findings redefine glycan recognition by noroviruses, challenging present models of infection.

Highlights

Noroviruses are single-stranded (+)−RNA viruses associated with acute gastroenteritis in mammalian hosts
A number of glycans were selected as ligands to probe binding to human and murine norovirus capsid proteins
We succeeded in providing high-yield expression protocols for stable isotope labeled human noroviruses (HuNoV) P-domains before [35,36,52], and recently we established such a protocol for murine norovirus infection (MNV) P-domains

Summary

Introduction

Noroviruses are single-stranded (+)−RNA viruses associated with acute gastroenteritis in mammalian hosts. Human noroviruses (HuNoV) are the leading cause for viral gastroenteritis worldwide, with the majority of norovirus outbreaks since 2012 having been caused by genogroup II, genotype 4 (GII.4) viruses [1,2,3]. Histo-blood group antigens (HBGAs) have been identified as critical structural determinants for HuNoV infection [4,5,6]. The host enzyme α-1,2-fucosyltransferase (FUT2) is essential for HBGA biosynthesis. A functional FUT2 enzyme defines the “secretor” phenotype, where HBGAs are present on the surface of intestinal epithelial cells and become secreted. Individuals lacking FUT2 activity are “non-secretors” and highly resistant against many HuNoV strains

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Results

Conclusion