Yeast ribosomal protein S3 has an endonuclease activity on AP DNA

Sang Oun Jung, Jae Yung Lee, Joon Kim

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)


The mammalian ribosomal protein S3 (rpS3) is a component of the 408 ribosomal subunit. It is known to function as a DNA repair enzyme, UV endonuclease III, which cleaves DNA that is irradiated by UV. It also has an endonuclease activity on AP DNA. In this report, the yeast ribosomal protein S3 (Rps3p) in S. cerevisiae was cloned, expressed in E. coli, and affinity-purified by 285 fold. Rps3p is composed of 240 amino acids and has a 78% amino acid similarity with the human counterpart that has 243 amino acids. The major difference in the amino acid sequence between the two proteins lies in most of the C-terminal 50 residues. Surprisingly, Rps3p only showed an endonuclease activity on AP DNA, but not on DNA that was irradiated with UV. The AP endonuclease activity of Rps3p was affected by pH, KCl, and β-mercaptoethanol, but Triton X-100 and EDTA did not affect the enzyme activity. From these results, both the mammalian rpS3 and Rps3p appear to be involved in DNA damage processing, but in different modes.

Original languageEnglish
Pages (from-to)84-90
Number of pages7
JournalMolecules and cells
Issue number1
Publication statusPublished - 2001 Aug 31


  • AP Endonuclease
  • DNA Repair
  • Ribosomal Protein S3
  • Rps3p

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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