# Unusual mechanisms of metal regulation down to single-cell single-molecule level

> **NIH NIH R01** · CORNELL UNIVERSITY · 2021 · $405,584

## Abstract

Defining how cells regulate the uptake and efflux of transition metals such as Zn and Cu is a key
component in elucidating cellular mechanisms of metal homeostasis. Bacterial model systems provide
paradigms for understanding metal-responsive gene regulation. In E. coli, the metalloregulator ZntR senses Zn
excess and activates Zn efflux, while Zur senses Zn sufficiency and represses Zn uptake, to keep this essential
metal at appropriate physiological levels in the cell. CueR, a homolog of ZntR, senses intracellular Cu to activate
Cu efflux/detoxification genes to keep this toxic metal minimal. The long-term goal here is to understand how
metal regulation in the cell can be manipulated for preventive and therapeutic purposes. Toward this goal, the
PI has established an internationally unique research program that applies and develops advanced single-
molecule single-cell approaches to interrogate and understand the mechanisms of bacterial metal regulation
both in vitro and in live cells, which are further enhanced by bulk biochemical/biophysical and protein/genetic
engineering approaches and established collaborations with biologists. The research has led to discoveries of
first-of-their-kind mechanisms of Cu/Zn-responsive transcriptional regulation, but new questions also emerged.
The objective of this renewal is to continue this program, as well as elucidate the mechanism that couples
CueR/ZntR regulation to DNA mechanical tension and the mechanism of Zur’s biphasic unbinding kinetics from
DNA, two novel phenomena the PI recently discovered. The premise of this research comprises the importance
of (bacterial) metal regulation in biology, the discovered novel and broadly relevant regulation mechanisms, and
the power of combining single-molecule/cell and bulk measurements. The proposed research contains two
specific aims, each with sub-aims: 1) Identify the mechanism of DNA-mechanical-tensioncoupled transcription
regulation by CueR/ZntR. This aim will test hypotheses based on the discoveries that CueR/ZntR’s unbinding
from DNA is modulated by chromosome condensation in cells and that CueR/ZntR can control RNAP actions on
DNA. 2) Identify the mechanism of biphasic unbinding kinetics of Zur from DNA. This aim will test hypotheses
regarding the preliminary results that apo/holo-Zur shows biphasic (i.e., repressed followed by facilitated)
unbinding kinetics from DNA with increasing intracellular protein concentrations. The research is significant
because it will elucidate novel molecular mechanisms of metalloregulators in regulating metal efflux and uptake,
as well as provide fundamental knowledge about cell biology of metals in general, for identifying causes or
developing preventions of diseases that involve similar regulation processes, and for helping the development
of (bio)chemical strategies to manipulate bacterial Zn/Cu regulation to impair pathogen growth. The research is
innovative because it applies/develops novel single-molecule manipulati...

## Key facts

- **NIH application ID:** 10152608
- **Project number:** 5R01GM109993-07
- **Recipient organization:** CORNELL UNIVERSITY
- **Principal Investigator:** Peng Chen
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $405,584
- **Award type:** 5
- **Project period:** 2014-07-01 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10152608

## Citation

> US National Institutes of Health, RePORTER application 10152608, Unusual mechanisms of metal regulation down to single-cell single-molecule level (5R01GM109993-07). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10152608. Licensed CC0.

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