Fig. 6

Analysis and expression of the mutated HBsAg-1 and HBsAg-2. The predicted mRNA secondary structures near the start codons of the mutated genes shows that the start codon AUG and the SD sequence are exposed from the stable stem-loop structural context (a, b). Furthermore, the accessibility analysis shows that the mutations allowed the exposition of the SD sequence in the mRNA of the mutated genes (c, d). The accessibility of the SD sequence in the mutated HBsAg-2 was significantly increased, while only a slight increase was noted in the mutated HBsAg-1. The expression of the mutated proteins was not very obvious in the SDS-PAGE analysis (e). However, the western blotting revealed weak reactive bands against the anti-HBsAg monoclonal antibody (f). This indicated that both mutated genes were weakly expressed