Table 1. Bacterial strains and plasmids used in this study.

Strain/plasmid	Genotype/relevant characteristics	Reference
Escherichia coli AG115	lacX74, galU, galK, araD139, strA, hsdR17/F’, lacIq lacZ::Tn10	(39)
Escherichia coli DH5α	supE44, hsdR17, recA1, endA1, gyrA96, thi-1, relA1	(11)
H.pylori J99	cagA+ vacA+ isolated from a patient with duodenal ulcer	(7)
pGEX-KG	Ptac, gst, oripBR322	(40)
GHPAQ41	ATCCa Molecular Biology, pUC18 derivative containing the entire H.pylori dnaA gene (1741 bp fragment)	(6)
pGEXHpdnaA(IV)	pGEX-KG derivative containing the 343 bp EcoRI–BamHI fragment encoding domain IV of H.pylori DnaA protein	This study
pOC170	pBR322 derivative containing the E.coli oriC region (five DnaA boxes)	(41)

^aATCC, American Type Culture Collection.