Expression and functional characterization of Helicobacter pylori catalase from baculovirus-infected insect cells

摘要

The catalase katA gene of Helicobacter pylori encodes an antioxidant enzyme to protect the bacteria from environmental toxic oxygen species.In this study,the baculovirus-insect cell expression system was used to express the full-length katA gene from the Taiwanese H.pylori TW-34 strain.Three lipidopteran insect cell lines(Sf9,Sf21,HighS)were evaluated to produce the recombinant catalase(KatA)using serum-containing and serum-free media.Large-scale production and purification of the recombinant KatA protein was achieved in a 2-1 bioreactor and through the use of immobilized metal affinity chromatography(MAC).Human gastric carcinoma AGS cells were co-cultured with H.pylori and the presence of the purified KatA protein resulted in a significant decrease in the apoptotic bodies observed in AGS cells.Our present study is the first report to demonstrate the functionality of recombinant KatA protein expressed in baculovirus-infected insect cells to protect human gastric cell apoptosis against H.pylori insults.