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First-order phase transition in large single duplex DNA induced by a nonionic surfactant
1Graduate School of Human Informatics, Nagoya University, Japan.
Biochemical and Biophysical Research Communications
|January 23, 1997
Summary
The nonionic surfactant Triton X-100 induces a coil-globule transition in T4DNA macromolecules. Increased surfactant concentration leads to DNA compaction, driven by osmotic pressure in concentrated solutions.
Area of Science:
- Biochemistry
- Physical Chemistry
- Molecular Biology
Background:
- Understanding DNA conformational changes is crucial for molecular biology.
- Nonionic surfactants can influence macromolecular behavior.
- Triton X-100 is a commonly used nonionic surfactant in biological studies.
Purpose of the Study:
- To investigate the effect of Triton X-100 on the conformational behavior of large T4DNA.
- To determine the concentration-dependent transition of T4DNA in the presence of Triton X-100.
Main Methods:
- Single-molecule observation using fluorescence microscopy.
- Systematic variation of Triton X-100 concentrations.
Main Results:
- T4DNA macromolecules exhibit a discrete coil-globule transition with increasing Triton X-100 concentration.
- At low concentrations, DNA exists in an elongated coil state.
- At high concentrations (50-90%), DNA forms compacted globules, driven by osmotic pressure.
Conclusions:
- Triton X-100 concentration is a key factor in T4DNA conformational changes.
- Osmotic pressure in concentrated surfactant solutions drives DNA compaction.
- This study provides insights into surfactant-induced DNA condensation.