中国生物工程杂志

Variations in the amino acid sequence of Infectious canine hepatitis virus (ICHV) structural proteins are the molecular basis for the antigen diversity of the virus.Majority of antigenic sites for the virus neutraliation are present on Loop1 and Loop2 of hexon.ICHV (the isolated strain) DNA was isolated and purified from the cultured MDCK cells.The Loop1 and Loop2 fragments were amplified by polymerase chain reaction(PCR) method,and then was connected by ligase T4.The target fragment was then connected with vector pET28a.The nucleotide sequence ecoding Loop1 and Loop2 was determined.The nucleotide sequence identity of Loop1 region between the isolated strain and CLL, RI261 and Toronto A26/61 strains is 100%, 100% and 83.8%, and the nucleotide sequence identity of Loop2 region between the isolated strain and CLL, RI261 and Toronto A26/61 strains is 88.1% , 88.1% and 99.3%, and amino acid identity is 93.6 , 93.6% and 98.6%.The recombinent Loop protein was expressed in E. coli and was approximately 36kDa in size,and then was purified.