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Updated: May 3, 2026

A Modified Yeast-one Hybrid System for Heteromeric Protein Complex-DNA Interaction Studies
Published on: July 24, 2017
An asymmetric heterodomain interface stabilizes a response regulator-DNA complex.
Anoop Narayanan1, Shivesh Kumar2, Amanda N Evrard3
11] Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, Indiana 47907, USA [2].
This study reveals how response regulators form stable DNA complexes to control gene expression. A unique interface between protein domains is key for this process in transcription factors.
Area of Science:
- Molecular biology
- Microbiology
- Structural biology
Background:
- Two-component signal transduction systems (TCS) mediate cellular responses to environmental stimuli.
- Response regulators (RRs) within TCS typically regulate transcription via DNA binding after phosphorylation.
- The mechanism of stable RR-DNA complex formation preceding RNA polymerase assembly remains largely unknown.
Purpose of the Study:
- To elucidate the molecular basis for stable response regulator-DNA complex formation.
- To investigate the role of intramolecular interfaces in RR-DNA complex stability.
- To understand the structural mechanisms underlying transcriptional regulation by RRs.
Main Methods:
- X-ray crystallography to determine the structures of KdpE-DNA complexes.
- Site-directed mutagenesis to probe the function of the identified intramolecular interface.
- Electrophoretic mobility shift assays (EMSAs) to assess DNA-binding stability.
Main Results:
- Structures of the OmpR/PhoB family response regulator KdpE bound to DNA were determined.
- A unique, asymmetric complex revealed an intramolecular receiver domain-DNA-binding domain (RD-DBD) interface in one RR monomer.
- This RD-DBD interface was found to be essential for forming stable KdpE-DNA complexes that support gene expression.
Conclusions:
- The identified intramolecular RD-DBD interface is critical for stabilizing response regulator-DNA interactions.
- This structural mechanism likely extends to a broad range of transcriptionally active response regulators.
- Findings provide insights into the regulation of gene expression by two-component systems.
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