Construction of the E.coli clone expressing adhesin BabA of Helicobacter pylori and evaluation of the adherence activity of BabA

Abstract

Objective: To construct a recombinant E.coli strain that highly expresses blood group Ag-binding adhesin (BabA) of Helicobacter pylori (Hp) and to assess the adherence activity of Hp BabA.

Methods: The gene fragment encoding BabA was amplified from Hp chromosomal DNA by PCR technique and inserted into prokaryotic expression vector pET-22b (+), which was then transformed into BL21 (DE3) E.coli strain for the expression of BabA recombinant protein. The adherence activity of Hp BabA obtained was assayed by counting under light microscope.

Results: DNA sequence analysis showed that the sequence of babA2 DNA was in agreement with that published in GenBank. The BabA recombinant protein amounted to 34.8% of the total protein of the bacterium after IPTG induction for 3 h at 37 degrees Celsius, and BabA-mediated adherence was confirmed in vitro.

Conclusion: A clone expressing biologically active Hp BabA has been obtained, which may facilitate further study of the function of the adhesin.