Interconvertible Lac Repressor-DNA Loops Revealed by Single-Molecule Experiments
Author Information
Author(s): Wong Oi Kwan, Guthold Martin, Erie Dorothy A, Gelles Jeff
Primary Institution: Brandeis University
Hypothesis
How do proteins like Lac repressor accommodate the formation of loops of different sizes on DNA?
Conclusion
Lac repressor can form stable looped structures with small loops even when the operators are out of phase, and a single looped complex can exist in an equilibrium of two different conformations.
Supporting Evidence
- Lac repressor can form looped complexes on both in-phase and out-of-phase di-operator molecules.
- Single-operator DNA bound to Lac repressor is not appreciably bent.
- The ability to switch between different loop structures may help maintain robust transcription regulation.
Takeaway
Lac repressor can bend DNA into loops, and it can switch between different shapes to help control how genes are turned on or off.
Methodology
Single-molecule kinetic and imaging techniques were used to examine loop formation from di-operator DNA constructs, utilizing atomic force microscopy and tethered particle motion.
Limitations
The study primarily focuses on in vitro conditions, which may not fully replicate in vivo dynamics.
Statistical Information
P-Value
p<0.025
Statistical Significance
p<0.025
Digital Object Identifier (DOI)
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