DNA damage is an integral component of hereditary diseases and aging. The overall goals of the proposed research are to examine fundamental questions concerning how DNA is damaged at the molecular level and to apply the knowledge gained from these studies to the design of therapeutic agents. Consequently, this research is valuable to understanding the etiology and treatment of diseases such as cancer, and provides insight into how we age. These studies are accomplished using a conglomeration of synthetic and physical organic chemistry along with techniques borrowed from molecular and radiation biology. Our general experimental approach invokes designing and synthesizing molecules that enable us to unambiguously generate reactive intermediates at defined sites in oligonucleotides. Using this approach, we can identify novel pathways of DNA damage, resolve mechanistic controversies, and probe the mechanism of action drugs and repair enzymes that interact with DNA.
Specific aims from the current funding period include: 1. Design of mechanism-based radiosensitizing agents. 2. Determine the roles that reactive intermediates that may not be identified by damaged nucleotides after the fact (""""""""invisible intermediate"""""""") play in DNA damage 3. Determine the ability of reactive species to amplify DNA damage by forming tandem and clustered lesions. 4. Determine the propensity for an oxidized nucleotide to catalyze formation of a premutagenic lesion.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
7R01GM054996-06
Application #
6519780
Study Section
Bio-Organic and Natural Products Chemistry Study Section (BNP)
Program Officer
Schwab, John M
Project Start
1997-07-01
Project End
2005-06-30
Budget Start
2002-07-01
Budget End
2003-06-30
Support Year
6
Fiscal Year
2002
Total Cost
$250,923
Indirect Cost
Name
Johns Hopkins University
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Zheng, Liwei; Greenberg, Marc M (2018) Traceless Tandem Lesion Formation in DNA from a Nitrogen-Centered Purine Radical. J Am Chem Soc 140:6400-6407
Sun, Huabing; Zheng, Liwei; Greenberg, Marc M (2018) Independent Generation of Reactive Intermediates Leads to an Alternative Mechanism for Strand Damage Induced by Hole Transfer in Poly(dA-T) Sequences. J Am Chem Soc 140:11308-11316
Zheng, Liwei; Griesser, Markus; Pratt, Derek A et al. (2017) Aminyl Radical Generation via Tandem Norrish Type I Photocleavage, ?-Fragmentation: Independent Generation and Reactivity of the 2'-Deoxyadenosin- N6-yl Radical. J Org Chem 82:3571-3580
Sun, Huabing; Taverna Porro, Marisa L; Greenberg, Marc M (2017) Independent Generation and Reactivity of Thymidine Radical Cations. J Org Chem 82:11072-11083
Zheng, Liwei; Greenberg, Marc M (2017) DNA Damage Emanating From a Neutral Purine Radical Reveals the Sequence Dependent Convergence of the Direct and Indirect Effects of ?-Radiolysis. J Am Chem Soc 139:17751-17754
Zheng, Liwei; Lin, Lu; Qu, Ke et al. (2017) Independent Photochemical Generation and Reactivity of Nitrogen-Centered Purine Nucleoside Radicals from Hydrazines. Org Lett 19:6444-6447
Cheng, Bokun; Zhou, Qingxuan; Weng, Liwei et al. (2017) Identification of proximal sites for unwound DNA substrate in Escherichia coli topoisomerase I with oxidative crosslinking. FEBS Lett 591:28-38
Greenberg, Marc M (2016) Reactivity of Nucleic Acid Radicals. Adv Phys Org Chem 50:119-202
Greenberg, Marc M (2016) Pyrimidine Nucleobase Radical Reactivity in DNA and RNA. Radiat Phys Chem Oxf Engl 1993 128:82-91
Pidugu, Lakshmi S; Flowers, Joshua W; Coey, Christopher T et al. (2016) Structural Basis for Excision of 5-Formylcytosine by Thymine DNA Glycosylase. Biochemistry 55:6205-6208

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