Mutational analysis of the damage-recognition and catalytic mechanism of human SMUG1 DNA glycosylase.

ABSTRACT: Single-strand selective monofunctional uracil-DNA glycosylase (SMUG1), previously thought to be a backup enzyme for uracil-DNA glycosylase, has recently been shown to excise 5-hydroxyuracil (hoU), 5-hydroxymethyluracil (hmU) and 5-formyluracil (fU) bearing an oxidized group at ring C5 as well as an uracil. In the present study, we used site-directed mutagenesis to construct a series of mutants of human SMUG1 (hSMUG1), and tested their activity for uracil, hoU, hmU, fU and other bases to elucidate the catalytic and damage-recognition mechanism of hSMUG1. The functional analysis of the mutants, together with the homology modeling of the hSMUG1 structure based on that determined recently for Xenopus laevis SMUG1, revealed the crucial residues for the rupture of the N-glycosidic bond (Asn85 an

SUBMITTER: Matsubara M 

PROVIDER: S-EPMC521670 | biostudies-literature | 2004

REPOSITORIES: biostudies-literature