# Single-molecule visualization and mechanisms of DNA recombination and intersecting DNA transactions

> **NIH NIH R35** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2020 · $811,580

## Abstract

Project Description  
 
The broad objective of this proposal is to understand the mechanism of homologous recombination and its 
relationship to chromosome maintenance in both Bacteria and Eukarya. Our approach is to reconstitute 
increasingly more complex reactions that recapitulate the steps of the homologous recombination process, 
using purified proteins from Escherichia coli and from Saccharomyces cerevisiae, and to use sophisticated 
biochemical and biophysical methods of analysis. In particular, we will use single-­molecule visualization to 
image key steps and intermediates of these complex biological processes. We have developed new 
experimental strategies for studying protein-­DNA interactions at the single-­molecule level. We devised several 
approaches wherein we could easily manipulate an individual DNA molecule and expose it to a variety of 
different proteins, enzymes, and buffers. Using fluorescent detection, we can image individual proteins on DNA 
or detect their action on individual DNA molecules, typically in real-­time. We propose to continue to use these 
approaches to study unresolved aspects of recombinational DNA repair and its interface with the important 
biological processes of chromatin remodeling and DNA replication. We seek to continue to address unresolved 
questions regarding the dynamic behavior of RecA/Rad51 nucleoprotein filaments and their regulation by 
protein mediators and modulators;; the mechanism by which RecA and Rad51 find DNA sequence homology;; 
the reconstitution increasingly more complex recombination processes using purified proteins;; the mechanism 
and function of DNA helicases and their partner proteins;; and understanding the mechanism of DNA 
transactions that intersect with recombination, namely, chromatin remodeling and DNA replication.

## Key facts

- **NIH application ID:** 9900833
- **Project number:** 5R35GM131900-02
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** Stephen Charles Kowalczykowski
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $811,580
- **Award type:** 5
- **Project period:** 2019-04-01 → 2024-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9900833

## Citation

> US National Institutes of Health, RePORTER application 9900833, Single-molecule visualization and mechanisms of DNA recombination and intersecting DNA transactions (5R35GM131900-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9900833. Licensed CC0.

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