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Structure of the cro repressor from bacteriophage lambda and its interaction with DNA
Nature
|April 30, 1981
Summary
The bacteriophage lambda cro repressor protein dimer binds operator DNA via alpha-helices in the major groove. C-terminal residues also contribute to this crucial DNA-protein interaction.
Area of Science:
- Molecular biology
- Structural biology
- Genetics
Background:
- The cro repressor protein is essential for bacteriophage lambda's lytic cycle.
- Understanding DNA-protein interactions is key to gene regulation.
Purpose of the Study:
- To elucidate the three-dimensional structure of the cro repressor protein.
- To determine how the cro repressor binds to its operator DNA.
Main Methods:
- X-ray crystallography to determine protein structure.
- Structural analysis of protein-DNA complex.
Main Results:
- The 66-amino acid cro repressor forms a dimer.
- The dimer binds to B-form DNA with coincident 2-fold axes.
- Alpha-helices within successive major grooves are critical for binding.
- C-terminal residues, disordered alone, aid DNA binding.
Conclusions:
- The cro repressor dimer utilizes specific alpha-helices and C-terminal regions for operator DNA recognition and binding.
- This structural insight provides a model for bacteriophage lambda gene regulation.