Nucleotide sequence determination and expression of X open reading frame of a hepatitis B virus adr subtype

Abstract

Nucleotide sequence encompassing the X open reading frame (ORF) of a hepatitis B virus subtype adr was determined and was compared with other reported sequences. Sequences between various isolates were highly conserved with about 94-98 % homology. Variations in nucleotide sequence appeared throughout the whole ORF. On the contrary, most of the amino acid substitions occurred in residues 30-40, the region at which no secondary structure was predicted. The X protein was successfully expressed in E. coll by a fusion to the C-terminus of a truncated ^-galactosidase. The yield of the fusion protein was 15 % of total cellular proteins.