OF WORK: Understanding the relationships between structure and function for a DNA enzyme holds the promise of allowing us to develop specific inhibitors and other modulators of the enzymes activity through rational design approaches. Although this idea is now fundamental in the field of structural biology, we are still in the earliest stages of bringing the approach to its full potential.Our studies of mammalian DNA polymerase beta have pioneered the use of a coordinated approach of structural studies (x-ray crystallography, NMR, and spectroscopy), biochemical studies and mammalian genetic studies. This approach has allowed us to establish the cellular role of DNA polymerase beta in mammalian base excision repair. And, the approach has allowed us to establish a solid framework for future studies of the role of individual amino acid residues in this enzyme in such important endpoints as the rate of DNA repair, coordination of DNA synthesis with DNA ligation, coordination of deoxyribose phosphate removal (lyase activity) with DNA synthesis, the fidelity of DNA synthesis, the fidelity of overall DNA base excision repair, and DNA lesion bypass. Rational drug design targeting these endpoints will allow us to strategically regulate base excision repair with DNA polymerase beta specific drugs.Detailed structure-function relationship studies of other base excision repair enzymes, such as XRCC1, DNA ligases I and III, AP endonuclease, and the various DNA glycosylases, will be undertaken in the future. Development of specific inhibitors or other modulators for these enzymes will allow us to strategically deregulate base excision repair in cells. This could have implications for chemotherapy and for understanding the role of DNA repair in preventing disease especially after exposure to environmental toxins. - base excision repair, DNA polymerase beta, structure-function, structural biology, fidelity, AP endonuclease, DNA synthesis, lyase, site-directed mutagenesis

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Intramural Research (Z01)
Project #
1Z01ES050158-03
Application #
6290027
Study Section
Special Emphasis Panel (LSB)
Project Start
Project End
Budget Start
Budget End
Support Year
3
Fiscal Year
1999
Total Cost
Indirect Cost
City
State
Country
United States
Zip Code
Ça?layan, Melike; Wilson, Samuel H (2018) Pol ? dGTP mismatch insertion opposite T coupled with ligation reveals promutagenic DNA repair intermediate. Nat Commun 9:4213
Oertell, Keriann; Kashemirov, Boris A; Negahbani, Amirsoheil et al. (2018) Probing DNA Base-Dependent Leaving Group Kinetic Effects on the DNA Polymerase Transition State. Biochemistry 57:3925-3933
Horton, Julie K; Stefanick, Donna F; Ça?layan, Melike et al. (2018) XRCC1 phosphorylation affects aprataxin recruitment and DNA deadenylation activity. DNA Repair (Amst) 64:26-33
Çaglayan, Melike; Wilson, Samuel H (2017) Role of DNA polymerase ? oxidized nucleotide insertion in DNA ligation failure. J Radiat Res 58:603-607
Ça?layan, Melike; Horton, Julie K; Dai, Da-Peng et al. (2017) Oxidized nucleotide insertion by pol ? confounds ligation during base excision repair. Nat Commun 8:14045
Shock, David D; Freudenthal, Bret D; Beard, William A et al. (2017) Modulating the DNA polymerase ? reaction equilibrium to dissect the reverse reaction. Nat Chem Biol 13:1074-1080
Horton, Julie K; Stefanick, Donna F; Zhao, Ming-Lang et al. (2017) XRCC1-mediated repair of strand breaks independent of PNKP binding. DNA Repair (Amst) 60:52-63
Prasad, Rajendra; Ça?layan, Melike; Dai, Da-Peng et al. (2017) DNA polymerase ?: A missing link of the base excision repair machinery in mammalian mitochondria. DNA Repair (Amst) 60:77-88
Howard, Michael J; Wilson, Samuel H (2017) Processive searching ability varies among members of the gap-filling DNA polymerase X family. J Biol Chem 292:17473-17481
Kirby, Thomas W; Gassman, Natalie R; Smith, Cassandra E et al. (2017) DNA polymerase ? contains a functional nuclear localization signal at its N-terminus. Nucleic Acids Res 45:1958-1970

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