RESUMO
Sequence analysis of a new norovirus (NV) isolated from Lanzou city of China was performed based on partial sequence of RNA dependent RNA polymerase (RdRp) and complete capsid protein (VP1) gene. The isolated strain CHN02/LZ35666 shared high sequence homology with GII-4 NVs. Nucleotide homologies of RdRp region and encoded capsid protein region were 90.4% -- 98.6% and 89.8% -- 95.7% , respectively, while amino acid homology of capsid protein region was 94.4% -- 97.4%. The analysis of GDD motif in RdRp region indicated this GDD motif of Lanzhou strain differed from those of the GII-4 predominant epidemic strains. Lanzhou strain formed an independent branch in GII-4 cluster in the phylogenetic tree based on nucleotide sequence of RdRp region and amino acid sequence of capsid protein. Sequence alignment revealed a mutation at the fourth key site of the receptor-binding interface in the strains isolated after 2002 compared with those of previous strains suggesting a possible change of binding pattern to HBGAs receptors.