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Structure and dynamics of the tetrameric mnt repressor and a model for its DNA complex
I M Nooren1, G E Folkers, R Kaptein
1a Department of NMR Spectroscopy, Bijvoet Center for Biomolecular Research , Utrecht University , Padualaan 8 , 3584 , CH Utrecht , The Netherlands.
Journal of Biomolecular Structure & Dynamics
|May 22, 2012
Summary
The Mnt repressor protein from bacteriophage P22 has flexible linkers between its DNA-binding and tetramerization domains. This structural flexibility allows the repressor to bind DNA operator sequences, causing significant bending.
Area of Science:
- Molecular Biology
- Structural Biology
- Biophysics
Background:
- The tetrameric Mnt repressor protein regulates gene expression in bacteriophage P22.
- Understanding the structure-function relationship of repressors is crucial for molecular biology.
Purpose of the Study:
- To elucidate the domain organization and flexibility of the tetrameric Mnt repressor.
- To investigate the structural basis of Mnt repressor-DNA complex formation.
Main Methods:
- Nuclear Overhauser Effect (NOE) and chemical shift analysis.
- 15N relaxation measurements.
- Gel-shift assays.
Main Results:
- The Mnt repressor comprises independent, structurally similar DNA-binding domains and a tetramerization domain connected by a flexible linker.
- 15N relaxation data indicate significant flexibility in the linker region, with no observed inter-domain interactions.
- A model suggests the tetramerization domain attaches to one N-terminal dimer, facilitating DNA binding and operator bending (~30°).
Conclusions:
- The Mnt repressor's modular structure and flexible linker are key to its DNA-binding mechanism.
- The proposed model accurately describes the Mnt repressor-DNA complex, highlighting domain arrangement and DNA bending.
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