ABSTRACT
@#Objective To analyze the evolutionary characteristics of GZ19 strain of G Ⅱ.4 norovirus(NoV) in China,and clarify its ability and mode of binding to receptors of histo-blood group antigens(HBGAs).Methods According to the sequence of ORF2 region in GZ19 strain,the evolutionary tree was constructed and the amino acid sequences at HBGA binding sites(HBSs) and key blocking epitopes were analyzed.P particles were expressed by prokaryotic expression system and purified.The obtained protein was identified by SDS-PAGE and indirect ELISA,and analyzed for the receptor binding characteristics of P particles by saliva binding and oligosaccharide binding assays.Results The GZ19 strain belonged to G Ⅱ.4Sydney [P31] lineage,of which the amino acid sequences of receptor binding sites and blocking epitopes were relatively conservative.It showed high homology with other G Ⅱ.4 Sydney [P31] strains in recent five years,while significant difference from G Ⅱ.4 Sydney 2012 original strain and G Ⅱ.4 Sydney [P16] strains.P particles only combined with A,B,O,AB secretory saliva and H-di oligosaccharide.Conclusion GZ19 strain represented the current evolutionary direction of G Ⅱ.4Sydney [P31] NoV.The successful expression of P particles and analysis of the binding characteristics with HBGA receptors laid a foundation of the research of epidemic evolution dynamics and vaccine development of G Ⅱ.4 NoVs in China.