Chlorella Virus Pyrimidine Dimer Glycosylase Excises Ultraviolet Radiation- and Hydroxyl Radical-Induced Products 4,6-Diamino-5-Formamidopyrimidine and 2,6-Diamino-4-Hydroxy-5-Formamidopyrimidine from DNA

Published

February 1, 2002

Author(s)

Pawel Jaruga, R Jabil, Amanda K. McCullough, H Rodriguez, M Miral Dizdar, R S. Lloyd

Abstract

A DNA glycosylase specific for UV radiation-induced pyrimidine dimers has been identified from chlorella virus Paramecium bursaria chlorella virus-1. This enzyme (Chlorella virus Pyrimidine dimer glycosylase [cv-pdgl) exhibits a 41% amino acid identity with endonuclease V from bacteriophage T4 (T4 pyrimidine dimer glycosylase [T4-pdgl), which is also specific for pyrimidine dimers. However, cv-pdg possesses a higher catalytic efficiency and broader substrate specificity than T4-pdg. The latter excises 4.6-diamino-5-formamidopyrimidine (FapyAde), a UV radiation- and hydroxyl radical-induced monomeric product of adenine in DNA. Using gas chromatography/isotope-dilution mass spectrometry and γ-irradiated DNA, we show in this work that cv-pdg also displays a catalytic activity for excision of FapyAde and, in addition, it excises 2, 6-diamino-4-hydroxy-5-formamidopyrimidine (FapyGua). Kinetic data show that FapyAde is a better substrate of cv-pdg than FapyGua. On the other hand, cv-pdg possesses a greater efficiency for the extension FapyAde than T4-pdg. These two enzymes exhibit different substrate specificities despite substantial structural similarities.

Citation

Photochemistry and Photobiology

Volume

75

Issue

2

Pub Type

Journals

Keywords

base-excision repair, chlorella virus, DNA glycosylase, formamidopyrimidine, gas chromatography/mass spectrometry, oxidative DNA damage

Citation

Jaruga, P. , Jabil, R. , McCullough, A. , Rodriguez, H. , , M. and Lloyd, R. (2002), Chlorella Virus Pyrimidine Dimer Glycosylase Excises Ultraviolet Radiation- and Hydroxyl Radical-Induced Products 4,6-Diamino-5-Formamidopyrimidine and 2,6-Diamino-4-Hydroxy-5-Formamidopyrimidine from DNA, Photochemistry and Photobiology (Accessed October 20, 2025)