Details

Autor(en) / Beteiligte

• Xu, Qing
• Morgan, Richard D.
• Roberts, Richard J.
• Blaser, Martin J.

Titel

Identification of Type II Restriction and Modification Systems in Helicobacter pylori Reveals Their Substantial Diversity among Strains

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 2000-08, Vol.97 (17), p.9671-9676

Ort / Verlag

United States: National Academy of Sciences of the United States of America

Erscheinungsjahr

2000

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• A total of 22 type II restriction endonucleases with 18 distinct specificities have been identified in six Helicobacter pylori strains. Among these 18 specificities are three completely new endonucleases, Hpy178III, Hpy99I, and Hpy188I, that specifically cleave DNA at TC-NNGA, CGWCG, and TCNGA sites, respectively. The set of endonucleases identified in each strain varies, but all have four- or five-base recognition sequences. Among 16 H. pylori strains, examination of the DNA modification status at the recognition sites of 15 restriction endonucleases reveals that each strain has a substantially different complement of type II modification systems. We conclude that the type II restriction-modification systems in H. pylori are highly diverse between strains, a unique characteristic of H. pylori. The diverse methylation status of H. pylori chromosomal DNA may serve as a new typing system to discriminate H. pylori isolates for epidemiological and clinical purposes. This study also demonstrates that H. pylori is a rich source of type II restriction endonucleases.