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Updated: Jun 27, 2026
06:10
Following Cell-fate in E. coli After Infection by Phage Lambda
Published on: October 14, 2011
Cleavage of bacteriophage lambda cI repressor involves the RecA C-terminal domain
Vitold E Galkin1, Xiong Yu, Jakub Bielnicki
1Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908-0733, USA.
Journal of Molecular Biology
|November 18, 2008
Summary
The RecA protein
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- The SOS response in Escherichia coli activates DNA repair genes via LexA repressor self-cleavage.
- RecA filaments catalyze LexA self-cleavage, but the role of RecA's C-terminal domain (CTD) is unclear.
- Bacteriophage lambda's cI repressor is a homolog of LexA and also undergoes RecA-mediated cleavage.
Purpose of the Study:
- To investigate the role of RecA's C-terminal domain (CTD) in repressor cleavage.
- To understand how RecA filament dynamics influence LexA and cI repressor cleavage rates.
Main Methods:
- Utilized electron microscopy and three-dimensional reconstructions.
- Analyzed RecA filament conformation and dynamics.
- Correlated RecA structure with repressor cleavage rates.
Main Results:
- RecA's CTD conformation and dynamics are modulated by DNA substrate and ATP analog.
- RecA CTD contacts coordinate the cI repressor during cleavage.
- Cleavage rates are highest when cI is coordinated by RecA's CTD.
Conclusions:
- RecA's CTD plays a crucial role in repressor cleavage, reconciling previous genetic and biochemical data.
- The findings provide a structural framework for understanding RecA-mediated SOS response regulation.
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