Purification and characterization of a novel DNA repair enzyme from the extremely radioresistant bacterium Rubrobacter radiotolerans

Ezat Asgarani, Hiroaki Terato, Kenjiro Asagoshi, Hamid Reza Shahmohammadi, Yoshihiko Ohyama, Takeshi Saito, Osamu Yamamoto, Hiroshi Ide

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

Rubrobacter radiotolerans is an extremely radioresistant bacterium. It exhibits higher resistance than the well-known radioresistant bacterium Deinococcus radiodurans, but the molecular mechanisms responsible for the radioresistance of R. radiotolerans remain unknown. In the present study, we have demonstrated the presence of a novel DNA repair enzyme in R. radiotolerans cells that recognizes radiation-induced DNA damages such as thymine glycol, urea residues, and abasic sites. The enzyme was purified from the crude cell extract by a series of chromatography to an apparent physical homogeneity. The purified enzyme showed a single band with a molecular mass of approximately 40 kDa in SDS-polyacrylamide gel electrophoresis, and was designated as R-endonuclease. R-Endonuclease exhibited repair activity for thymine glycol, urea residues, and abasic sites present in plasmid DNA, but did not act on intact DNA, UV-irradiated DNA and DNA containing reduced abasic sites. The substrate specificity together with the salt and pH optima suggests that R-endonuclease is a functional homolog of endonuclease III of Escherichia coli.

Original languageEnglish
Pages (from-to)19-34
Number of pages16
JournalJournal of radiation research
Volume41
Issue number1
DOIs
Publication statusPublished - Mar 2000
Externally publishedYes

Keywords

  • Endonuclease III homologue
  • Enzyme purification
  • Radioresistant bacteria
  • Repair enzyme
  • Thymine glycol

ASJC Scopus subject areas

  • Radiation
  • Radiology Nuclear Medicine and imaging
  • Health, Toxicology and Mutagenesis

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