鸭肝炎病毒基因的生物信息学分析及多聚蛋白的加工预测

Bioinformatics analysis and prediction of polyprotein processing of duck hepatitis virus

对NCBIGenBank中登录的鸭肝炎病毒1型(DHV-1)全基因组及VP1基因进行生物信息学分析,27株DHV-1全基因组序列其核苷酸同源性分别为93.3%～99.8%、多聚蛋白氨基酸序列同源性则达97%～99.8%,DHV-1和其他小RNA科病毒的多聚蛋白的氨基酸序列同源性均低于30%,多聚蛋白氨基酸序列进化分析显示DHV-1在小RNA科病毒上形成一个独立的进化分支。因此,应在小RNA病毒科中设立一个DHV-1的新病毒属。分析发现,在DHV-1 VP1区存在多个免疫优势辅助性T淋巴细胞抗原位点及其抗原决定簇。在DHV-1多聚蛋白的第1757aa～1761aa位,出现3C蛋白酶(3Cpro)的共有基序Gly-Ser-Cys-Gly-Gly,同时发现在751aa/752aa处存在自我切割基序NPG↓P。推测在整个DHV-1多聚蛋白的切割过程中首先进行NPG↓P切割,形成P1,P2-P3前体蛋白,进而再由3Cpro对2个前体蛋白进行二级加工,最终DHV-1多聚蛋白总共被切割成12个成熟产物,形成其结构蛋白与非结构蛋白。

The complete genome sequence of duck hepatitis virus 1 （DHV-1） from the databank of the National Center for Biotechnology Information （NCBI） was analysed. Sequence comparison revealed significant sequence homology （93.3 % to 99.8 % in nucleotides sequences and 97 % to 99.8 % in amino acid sequences） among 27 DHV-1 strains, while amino acid sequence identities between polyprotein of DHV-1 and other picornaviruses was less than 30 %. Although DHV-1 has been classified as an unassigned virus in the Picornaviridae family, some unique characteristics of DHV-1 genome and phylogenetic analysis of DHV-1 suggested a new genus in the Picornaviridae. There were several immuno-dominant T cell epitopes and antigenic determinants in the region of VP1 of DHV-1, with the Consensus motif （Gly-Ser-Cys-Gly-Gly） of 3Cpro between 1 757 aa and 1 761 aa and the autocleavage motif NPG↓P at the position 751/752 aa. It is predicted that DHV-1 polyprotein appears to be cleaved into 12 mature products, forming its structural and nonstructural proteins.