Related Experiment Videos
CRP:cAMP complex binding to the lac operator region induces a structural change in lac DNA
1Department of Chemistry, Kyungwon University, Sungnam, Korea.
Molecules and Cells
|June 30, 1997
Summary
The cyclic AMP receptor protein (CRP) complex alters DNA structure when binding to the lac control region. Specifically, binding to the operator-proximal site induces a significant structural change in lac DNA.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- The lac control region is crucial for regulating lactose metabolism in bacteria.
- Cyclic AMP receptor protein (CRP) is a key transcription factor that modulates gene expression.
- Understanding DNA structural changes upon protein binding is vital for deciphering gene regulation mechanisms.
Purpose of the Study:
- To investigate DNA structural alterations induced by cAMP receptor protein (CRP) binding to the lac control region.
- To correlate these structural changes with specific CRP binding events.
Main Methods:
- Measurement of the molar cyclization factor (jM) to assess DNA structural changes.
- Utilizing a 231 bp DNA fragment of the lac control region.
- Varying concentrations of the CRP:cAMP complex.
Main Results:
- Increases in jM were observed at low to moderate CRP:cAMP complex concentrations, correlating with binding to the promoter-proximal CRP site.
- At higher CRP:cAMP concentrations (>200 nM), decreases in jM were observed.
- These decreases correlated with CRP binding to both promoter-proximal and operator-proximal CRP binding sites.
Conclusions:
- CRP:cAMP complex binding to the lac control region induces measurable changes in DNA structure.
- Binding to the operator-proximal CRP site specifically triggers a structural alteration in lac DNA.