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Updated: Aug 8, 2026
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Iterative Optimization of DNA Duplexes for Crystallization of SeqA-DNA Complexes
Published on: November 1, 2012
A model for catabolite activator protein binding to supercoiled DNA
Summary
Catabolite activator protein (CAP) binding to DNA induces a solenoidal coil, facilitating transcription initiation in Escherichia coli. This interaction model explains CAP
Area of Science:
- Molecular Biology
- Genetics
- Biophysics
Background:
- Catabolite activator protein (CAP) is crucial for transcription initiation of catabolite-sensitive genes in Escherichia coli.
- CAP is a dimeric protein with known geometrical features influencing its DNA interactions.
- Previous studies have characterized CAP-DNA complexes and their properties.
Purpose of the Study:
- To propose a model for the interaction between Catabolite activator protein (CAP) and DNA.
- To explain how CAP binding influences DNA structure and facilitates transcription.
- To relate CAP-DNA interaction to RNA polymerase activity and gene regulation.
Main Methods:
- Geometric analysis of the CAP molecule.
- Modeling CAP interaction with right-handed B-DNA major grooves.
- Integration of existing data on CAP-DNA complexes and DNA unwinding experiments.
Main Results:
- A model where CAP bridges adjacent loops of a DNA solenoidal coil.
- CAP binding induces a left-handed solenoidal loop in supercoiled DNA.
- This induced loop may create a unique binding site for RNA polymerase, facilitating DNA unwinding.
Conclusions:
- The proposed model is consistent with experimental data on CAP-DNA interactions.
- CAP-induced DNA conformational changes are linked to enhanced RNA polymerase activity.
- Promoter sequence symmetry may play a role in differential gene transcription control via CAP.
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