Recombinant Helicobacter pylori catalase

Abstract

Aim: To construct a recombinant strain which highly expresses catalase of Helicobacter pylori (H. pylori) and assay the activity of H. pylori catalase.

Methods: The catalase DNA was amplified from H. pylori chromosomal DNA with PCR techniques and inserted into the prokaryotie expression vector pET-22b (+), and then was transformed into the BL21 (DE3) E.coli strain which expressed catalase recombinant protein. The activity of H. pylori catalase was assayed by the Beers and Sizers.

Results: DNA sequence analysis showed that the sequence of catalase DNA was the same as GenBank's research. The catalase recombinant protein amounted to 24.4 % of the total bacterial protein after induced with IPTG for 3 hours at 37 degrees and the activity of H. pylori catalase was high in the BL21 (DE3) E.coli strain.

Conclusion: A clone expressing high activity H. pylori catalase is obtained, laying a good foundation for further studies.

Figure 1

Agarose gel electrophoresis of PCR products and plasmid pET-CAT digested with restriction enzymes. Lane 1: DNA marker; Lane 2: PCR product; Lane 3: pET-22b (+)/Xho I; Lane 4: pET-CAT/Xho I; Lane 5: pET-CAT/Nco I + Not I.

Figure 2

SDS-PAGE analysis of catalase recombinant protein expressed in BL21 (DE3). Lane 1: Molecular weight marker (20, 30, 43, 67, 94) × 10³; Lane 2: BL21 (pET-CAT) cells before induction; Lane 3: BL21 (pET-CAT) cells after 3 h induction with IPTG; Lane 4: BL21 (pET-CAT) cells periplasm protein after 3 h induction with IPTG; Lane 5: sonicate supernatant of BL21 (pET-CAT) cells after 3 h induction with IPTG; Lane 6: inclusion body of BL21 (pET-CAT) cells after 3 h induction with IPTG; Lane 7: control strain BL21 (pET) before induction; Lane 8: control strain BL21 (pET) after 3 h induction with IPTG.