Download MendeleyAn unconventional family 1 uracil DNA glycosylase in Nitratifractor salsuginis.
Li, J., Chen, R., Yang, Y., Zhang, Z., Fang, G.C., Xie, W., Cao, W.(2017) FEBS J 284: 4017-4034
- PubMed: 28977725
- DOI: https://doi.org/10.1111/febs.14285
- Primary Citation of Related Structures:
5X3G, 5X3H - PubMed Abstract:
The uracil DNA glycosylase superfamily consists of at least six families with a diverse specificity toward DNA base damage. Family 1 uracil N-glycosylase (UNG) exhibits exclusive specificity on uracil-containing DNA. Here, we report a family 1 UNG homolog from Nitratifractor salsuginis with distinct biochemical features that differentiate it from conventional family 1 UNGs. Globally, the crystal structure of N. salsuginisUNG shows a few additional secondary structural elements. Biochemical and enzyme kinetic analysis, coupled with structural determination, molecular modeling, and molecular dynamics simulations, shows that N. salsuginisUNG contains a salt bridge network that plays an important role in DNA backbone interactions. Disruption of the amino acid residues involved in the salt bridges greatly impedes the enzymatic activity. A tyrosine residue in motif 1 (GQDPY) is one of the distinct sequence features setting family 1 UNG apart from other families. The crystal structure of Y81G mutant indicates that several subtle changes may account for its inactivity. Unlike the conventional family 1 UNG enzymes, N. salsuginisUNG is not inhibited by Ugi, a potent inhibitor specific for family 1 UNG. This study underscores the diversity of paths that a uracil DNA glycosylase may take to acquire its unique structural and biochemical properties during evolution.
Organizational Affiliation:
Department of Genetics and Biochemistry, Clemson University, SC, USA.
