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Iterative Optimization of DNA Duplexes for Crystallization of SeqA-DNA Complexes
Published on: November 1, 2012
Crystal structure of the lambda repressor C-terminal domain provides a model for cooperative operator binding
C E Bell1, P Frescura, A Hochschild
1The Johnson Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia 19104, USA.
Cell
|July 13, 2000
Summary
This study reveals the structural basis for cooperative DNA binding by the lambda repressor. The crystal structure shows how two repressor dimers interact to bind adjacent operator sites, explaining gene regulation.
Area of Science:
- Molecular biology
- Structural biology
- Genetics
Background:
- Cooperative DNA binding by transcription factors is crucial for gene regulation.
- Detailed structural models explaining this cooperativity are often lacking.
- The lambda repressor (c1) is a model system for studying cooperative binding.
Purpose of the Study:
- To determine the X-ray crystal structure of the C-terminal domain of the lambda repressor.
- To elucidate the molecular interactions mediating cooperative DNA binding.
- To develop a structural model for the binding of two lambda repressor dimers to adjacent operator sites.
Main Methods:
- X-ray crystallography
- Multi-wavelength anomalous diffraction (MAD)
- Integration of structural, genetic, and biochemical data.
Main Results:
- The crystal structure of the lambda repressor C-terminal domain was determined.
- The structure captured the dimer-dimer interactions responsible for cooperativity.
- Two repressor dimers were observed to associate around a 2-fold axis of symmetry.
Conclusions:
- The structure provides a molecular basis for understanding cooperativity in lambda repressor binding.
- This work offers insights into the general mechanisms of transcription factor cooperativity.
- A model for cooperative binding of two lambda repressor dimers to adjacent operator sites is proposed.
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