Identification of a New Uracil-DNA Glycosylase Family by Expression Cloning Using Synthetic Inhibitors
Document Type
Article
Department
Biology (HMC), Chemistry (HMC)
Publication Date
1999
Abstract
Background: The cellular environment exposes DNA to a wide variety of endogenous and exogenous reactive species that can damage DNA, thereby leading to genetic mutations. DNA glycosylases protect the integrity of the genome by catalyzing the first step in the base excision–repair of lesions in DNA.
Results: Here, we report a strategy to conduct genome-wide screening for expressed DNA glycosylases, based on their ability to bind to a library of four synthetic inhibitors that target the enzyme's active site. These inhibitors, used in conjunction with the in vitro expression cloning procedure, led to the identification of novel Xenopus and human proteins, xSMUG1 and hSMUG1, respectively, that efficiently excise uracil residues from DNA. Despite a lack of statistically significant overall sequence similarity to the two established classes of uracil-DNA glycosylases, the SMUG1 enzymes contain motifs that are hallmarks of a shared active-site structure and overall protein architecture. The unusual preference of SMUG1 for single-stranded rather than double-stranded DNA suggests a unique biological function in ridding the genome of uracil residues, which are potent endogenous mutagens.
Conclusions: The ‘proteomics’ approach described here has led to the isolation of a new family of uracil-DNA glycosylases. The three classes of uracil-excising enzymes (SMUG1 being the most recently discovered) represent a striking example of structural and functional conservation in the almost complete absence of sequence conservation.
Rights Information
© 1999 Elsevier Science Ltd. All rights reserved.
DOI
10.1016/S0960-9822(99)80087-6
Recommended Citation
Karl A. Haushalter, P. Todd Stukenberg, Marc W. Kirschner, Gregory L. Verdine, Identification of a new uracil-DNA glycosylase family by expression cloning using synthetic inhibitors, Current Biology, Volume 9, Issue 4, 25 February 1999, Pages 174-185, ISSN 0960-9822, http://dx.doi.org/10.1016/S0960-9822(99)80087-6. (http://www.sciencedirect.com/science/article/pii/S0960982299800876)
