Characterization of two cryptic Helicobacter pylori plasmids: a putative source for horizontal gene transfer and gene shuffling.

ABSTRACT: Many Helicobacter pylori isolates carry cryptic plasmids of extremely variable size. In this study we analyzed two H. pylori plasmids, pHel4 and pHel5, from H. pylori strains P8 and P29, respectively. Plasmid pHel4 consists of 10,970 bp, constituting 15 putative open reading frames (ORFs), whereas pHel5 consists of 18,291 bp, constituting 17 ORFs. The findings that both plasmids encode a conserved RepA protein and that both have an origin of replication containing an iteron place them in the group of theta plasmids. In pHel4, the products of the overlapping orf4C, orf4D, orf4E, and orf4F sequences are homologous to MobA, MobB, MobC, and MobD, encoded by colicinogenic plasmids, suggesting that pHel4 might be mobilizable. A further putative operon consists of orf4B and orf4A, the products of

SUBMITTER: Hofreuter D 

PROVIDER: S-EPMC135030 | biostudies-literature | 2002 May

REPOSITORIES: biostudies-literature