# Project 4 - Single Molecule Analysis of Interactions Between BER Enzymes and their Targets

> **NIH NIH P01** · UNIVERSITY OF VERMONT & ST AGRIC COLLEGE · 2021 · $367,165

## Abstract

SUMMARY 
The central hypothesis of this Program Project is that defects in base excision repair (BER) drive human 
carcinogenesis and affect responses to cancer treatments. To test this hypothesis, we are using our strengths 
in fundamental biochemistry, molecular biology, structural biology and biophysics to examine human genetic 
variation in the BER enzymes. Our program is informed and driven by the identification of germline and tumor- 
associated enzyme variants that may alter the DNA repair capacity of human BER enzymes. The single- 
molecule approaches proposed in Project 4 will provide insights into how the human DNA glycosylases and 
the downstream enzymes in BER search for their targets in a sea of undamaged DNA as well as in a 
chromatin milieu. We hypothesize that, as we have shown for their bacterial homologs, the human DNA 
glycosylases, which remove oxidized bases, scan the DNA in a rotational manner employing an amino acid 
wedge to search for base damage. We further postulate that the downstream enzymes search for the product- 
bound prior enzyme in the pathway and that DNA compacted into nucleosomes may reduce BER enzyme 
diffusion rates. These hypotheses will be tested by: Elucidating the real-time DNA damage search behavior of 
the human DNA glycosylases and their variants (Aim 1); elucidating the spatial relationships and interactions 
between enzymes in the BER pathway relative to the site of DNA damage (Aim 2); and determining the 
diffusive behavior of the BER enzymes in the context of chromatin (Aim 3). To do this, we will examine the 
diffusive properties of the BER enzymes on both undamaged and site-specifically damaged DNA and on 
chromatin as well as on DNA or chromatin bound by the prior enzyme in the pathway. We also will determine if 
the diffusion of glycosylases is affected by mutations in putative reading head amino acids or by germline and 
tumor-associated variants that potentially affect the BER search process.

## Key facts

- **NIH application ID:** 10146971
- **Project number:** 5P01CA098993-15
- **Recipient organization:** UNIVERSITY OF VERMONT & ST AGRIC COLLEGE
- **Principal Investigator:** Andrea J Lee
- **Activity code:** P01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $367,165
- **Award type:** 5
- **Project period:** 2004-09-03 → 2025-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10146971

## Citation

> US National Institutes of Health, RePORTER application 10146971, Project 4 - Single Molecule Analysis of Interactions Between BER Enzymes and their Targets (5P01CA098993-15). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10146971. Licensed CC0.

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