[Cloning, expression and identification of catalase of Helicobacter pylori].
OBJECTIVE
To construct the recombinant plasmid containing catalase (KatA) of Helicobacter pylori (Hp), analyze its nucleic acid sequence, express it in E. coli and study its antigenicity.


METHODS
KatA fragments were amplified from Hp chromosomal DNA by PCR. Its T-A was cloned, sequenced and compared with other HP strains on the GenBank. Then the gene cloned into pGEX-4T-1 fusion expression vector was expressed in E. coli and purified by GST-affinity chromatography. The purified product was used to identify 29 stains of mouse anti Hp monoclonal antibodies and analyze antigenicity with serum of Hp-infected patients by Western blot.


RESULTS
KatA fragments were composed of 1,515 bp (GenBank No. DQ333889) and the nucleotide homology with other Hp strains on the GenBank was 96%-97%. 85 kDa of the recombinant KatA-pGEX-4T-1 was expressed in E. coli. 4 of 29 anti-Hp mouse monoclonal antibodies were against KatA. Western blot analysis proved that KatA was specifically recognized in the serum of Hp-infected patients.


CONCLUSIONS
The recombinant KatA has original antigenicity. It is of great value to clinical sero-diagnosis and vaccine study of Hp.
Li
Yan
Y
Department of Tropical Diseases, School of Biotechnology, Southern Medical University, Guangzhou 510515, China. lyinf@163.com
Ning
Yun-shan
YS
Long
Min
M
Dong
Wen-qi
WQ
Li
Ming
M
D000911:Antibodies, Monoclonal / Q000032:analysis / Q000276:immunology; D002374:Catalase / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification*; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D016481:Helicobacter Infections / Q000097:blood / Q000276:immunology; D016480:Helicobacter pylori / Q000201:enzymology*; D006801:Humans; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
D000911:Antibodies, Monoclonal; D002374:Catalase; D004262:DNA Restriction Enzymes