Construction of a prokaryotic expression system of vacA gene and detection of vacA gene, VacA protein in Helicobacter pylori isolates and ant-VacA antibody in patients’ sera

Figure 3 Expression of rVacA induced by IPTG at different concentrations. Lane 1, the protein marker; lanes 2-4, IPTG at 1.0, 0.5, 0.1 mmol/L respectively; lanes 5 and 6, bacterial pre-cipitate and supernatant with IPTG at 0.5 mmol/L, respectively; and lane 7, the negative control.ucleotide sequence from strain NCTC 11637, respectively, but the encoded amino acid residuals are not altered (are the changes correct?). “*” means stop codon.