New preparation of PM2 phage DNA and an endonuclease assay for a single-strand break

Sang Oun Jung, Chung Kyoon Auh, Jae Chun Ryu, Joon Kim

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


PM2 is a bacteriophage which has closed circular double-stranded DNA as a genome, which is the sole source for endonuclease assay for a single strand break in the fmol range. Therefore, it is important to isolate PM2 DNA with low control nicks for the endonuclease assay. Usually, the isolation method of phage DNA is to use ultracentrifugation which takes at least 4 days. In this report, a fast and effective method which takes only 2 days was developed to purify DNA using polyethylene glycol (PEG) 8000 and the yields of phage DNA isolated by these two methods were compared. The method using PEG 8000 increased the yield of PM2 DNA from 31.2% to 45.2%, and decreased the nick from 17.1% to 13.1%. Recently, the complete PM2 DNA genome sequence of 10,079 bp was published. The exact number of nucleotides of PM2 DNA is important for the correct enzyme assay which measures nicks generated by an endonuclease. The correct calculation of endonuclease activity of rpS3 for nick-circle assay was performed to measure single-strand breaks in this report.

Original languageEnglish
Pages (from-to)223-229
Number of pages7
JournalAntonie van Leeuwenhoek, International Journal of General and Molecular Microbiology
Issue number3
Publication statusPublished - 2003

Bibliographical note

Funding Information:
This work was supported by KOSEF grant 99-1-20900-005-5 and by grant FG3102 from the Ministry of Science and Technology of Korea.


  • DNA repair
  • DNA single-strand break
  • Endonuclease
  • Nick circle assay
  • PM2 phage
  • Rps3

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology


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