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Purification and properties of phage P22 c2 repressor
European Journal of Biochemistry
|January 2, 1978
Summary
The purified c2 repressor from phage P22 specifically binds to phage DNA, with reduced affinity for a mutant operator. Dissociation rates vary with temperature, indicating conditional binding strength.
Area of Science:
- Molecular Biology
- Virology
- Biochemistry
Background:
- Bacteriophage P22 utilizes a c2 repressor protein for genetic regulation.
- Understanding repressor-operator interactions is crucial for phage lifecycle control.
Purpose of the Study:
- To purify and characterize the c2 repressor of phage P22.
- To investigate the binding specificity and kinetics of c2 repressor with phage DNA.
- To compare c2 repressor binding to lambda cI repressor.
Main Methods:
- Purification of homogeneous c2 repressor protein.
- DNA binding assays using lambdaimm21 and P22 DNA.
- Measurement of dissociation rates of repressor-DNA complexes at varying temperatures.
- Comparison of dissociation rates with lambda cI repressor.
Main Results:
- The c2 repressor was purified to homogeneity.
- Specific binding of c2 repressor to lambdaimm21 and P22 DNA was observed.
- Reduced affinity for the P22 virB operator mutant was detected.
- Dissociation rates increased with temperature (0.02 min-1 at 0°C to 0.17 min-1 at 32°C).
Conclusions:
- The c2 repressor exhibits specific DNA binding properties.
- Temperature influences the stability of c2 repressor-DNA complexes.
- Comparative analysis with lambda cI repressor provides insights into repressor function.