A novel hepatitis B virus mutant with A-to-G at nt551 in the surface antigen gene

Figure 1 The complete nucleotide sequence of the mutant S gene. The A-to-G mutation site at nt551 of HBV genome is in bold letter. The underlined are the EcoRI-like site, the initiation codon of HBsAg and the amino acid codon (ATG to GTG) respectively. The first C of the EcoRI-like site (GAACTC) is counted as nt1. The GenBank accession number of the sequence is AF052576.

Figure 2 Comparative analysis of the HBsAg 'a' determinant coding regions of different HBV genomes. HBsAg 'a' determinant is a conformational epitope which has a special two-loop construction kept by the disulfide bonds between Cys124 and Cys137, Cys139 and Cys147, respectively. 48 HBV genome sequences were downloaded from National Center for Biotechnology Information (NCBI), USA (http://www.ncbi.nlm.nih.gov). “Cene names” are their names in the original gene databases. Here the ※ labeled ones are from DDBJ, the labeled are from EMBL, and the § labeled are from GenBank.