Characterization of a Novel 8-Oxoguanine-DNA Glycosylase Activity in Escherichia Coli and Identification of the Enzyme as Endonuclease VIII

Published

September 1, 2000

Author(s)

T. K. Hazra, T. Izumi, R Venkataraman, Y W. Kow, M. Dizdaroglu, Somenath Mitra

Abstract

8-oxoguanine (G*), induced by reactive oxygen species, is mutagenic because it mispairs with A. The major G*-DNA glycosylase (OGG), namely, OGG1 in eukaryotes, or MutM in Escherichia coli, excises G* when paired in DNA with C, G and T, but not A, presumably because removal of G* from a G* A pair would be mutagenic. However, repair of G* will prevent mutation when it is incorporated in the nascent strand opposite A. This could be carried out by a second OGG, OGG2, identified in yeast and human cells. We have now characterized a new OGG activity E. coli and then identified it to be endonuclease VIII (Nei) discovered as a damaged pyrimidine-specific DNA glycosylase. Nei shares sequence homology and reaction mechanism with MutM, and is similar to human OGG2 in being able to excise G* when paired with A (or G). Kinetic analysis of wild type Nei showed that it has significant activity for excising G* relative to Dihydrouracil. The presence of OGG2 type enzyme in both E. coli and Eukaryotes, which is at least as efficient in excision G* from a G* A(or G) pair as from a G* C pair, supports the possibility of G* repair in the nascent DNA strand.

Citation

Journal of Biological Chemistry

Volume

275

Issue

No. 36

Pub Type

Journals

Keywords

DNA glycosylases, DNA repair, excision kinetics, mismatch repair, ogg2 protein, oxidative DNA damage

Citation

Hazra, T. , Izumi, T. , Venkataraman, R. , Kow, Y. , Dizdaroglu, M. and Mitra, S. (2000), Characterization of a Novel 8-Oxoguanine-DNA Glycosylase Activity in Escherichia Coli and Identification of the Enzyme as Endonuclease VIII, Journal of Biological Chemistry (Accessed December 26, 2024)