title: Characterization of a wide range base-damage-endonuclease activity of mammalian rpS3.
abstract: Mammalian rpS3, a ribosomal protein S3 with a DNA repair endonuclease activity, nicks heavily UV-irradiated DNA and DNA containing AP sites. RpS3 calls for a novel endonucleolytic activity on AP sites generated from pyrimidine dimers by T4 pyrimidine dimer glycosylase activity. This study revealed that rpS3 cleaves the lesions including AP sites, thymine glycols, and other UV damaged lesions such as pyrimidine dimers. This enzyme does not have a glycosylase activity as predicted from its amino acid sequence. However, it has an endonuclease activity on DNA containing thymine glycol, which is exactly overlapped with UV-irradiated or AP DNAs, indicating that rpS3 cleaves phosphodiester bonds of DNAs containing altered bases with broad specificity acting as a base-damage-endonuclease. RpS3 cleaves supercoiled UV damaged DNA more efficiently than the relaxed counterpart, and the endonuclease activity of rpS3 was inhibited by MgCl2 on AP DNA but not on UV-irradiated DNA.
authors.affiliation: Laboratory of Biochemistry, School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
authors.forename: Sang Hwa
authors.initials: SH
authors.lastname: Kim
authors.forename: Jae Yung
authors.initials: JY
authors.lastname: Lee
authors.forename: Joon
authors.initials: J
authors.lastname: Kim
mesh_terms: D004247:DNA / Q000737:chemistry* / Q000528:radiation effects*; D004249:DNA Damage; D004260:DNA Repair; D045643:DNA Repair Enzymes / Q000737:chemistry*; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000737:chemistry; D003850:Deoxyribonuclease I / Q000737:chemistry; D004706:Endodeoxyribonucleases / Q000737:chemistry*; D009097:Multienzyme Complexes / Q000737:chemistry*; D009711:Nucleotides / Q000737:chemistry* / Q000528:radiation effects; D012269:Ribosomal Proteins / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D009097:Multienzyme Complexes; D009711:Nucleotides; D012269:Ribosomal Proteins; C044152:ribosomal protein S3; C032219:UV endonuclease; D004247:DNA; D004706:Endodeoxyribonucleases; D003850:Deoxyribonuclease I; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D045643:DNA Repair Enzymes