# Dynamics of processivity clamp proteins in bacterial DNA replication

> **NIH NIH R01** · NORTHEASTERN UNIVERSITY · 2021 · $298,202

## Abstract

Project Summary
Accurate and efficient DNA replication is critical for the survival of all organisms. The overall goal of this project
is to understand how the molecular dynamics of the processivity clamp regulate its interactions that are central
to efficient DNA replication. The focus of this proposal is on the Escherichia coli beta clamp, which is a ring-
shaped dimeric protein that encircles DNA and provides a binding platform for other proteins to access DNA.
Processivity clamps also increase the efficiency of DNA replication by tethering DNA polymerases to DNA and
increasing their processivity. Appropriate loading of the beta clamp is critical for regulation of events at the
replication fork and for efficient DNA replication. Our central hypothesis, which is supported by our preliminary
data, is that trapping of specific transiently sampled beta clamp conformations by the clamp loader underlies
loading of beta onto DNA and determines the efficiency of this process. To test this hypothesis, in aim 1, we
will design variants of the beta clamp with altered stability or asymmetry and determine the thermal stability
and oligomeric state of these altered clamps. We will also probe the interactions of the altered clamps with the
clamp loader. In aim 2, we will determine the dynamics of the beta clamp alone and in complex with clamp
loader by Transverse Relaxation Optimized SpectroscopY (TROSY) NMR relaxation and hydrogen exchange
measurements. In aim 3, we will determine the biological functions of the designed clamp protein variants,
including their ability to interact with and be loaded onto DNA by the clamp loader, and to function in
processive DNA replication. Correlating the dynamics of the beta clamp with its proficiency in these different
activities will provide important insights into the relationship between clamp dynamics and function. Moreover,
this work will provide fundamental insights into the roles of protein dynamics in regulating protein-protein
interactions.

## Key facts

- **NIH application ID:** 10245024
- **Project number:** 5R01GM123239-05
- **Recipient organization:** NORTHEASTERN UNIVERSITY
- **Principal Investigator:** PENNY J BEUNING
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $298,202
- **Award type:** 5
- **Project period:** 2017-09-30 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10245024

## Citation

> US National Institutes of Health, RePORTER application 10245024, Dynamics of processivity clamp proteins in bacterial DNA replication (5R01GM123239-05). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10245024. Licensed CC0.

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