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Updated: Jul 9, 2026
08:48
Stretching Short Sequences of DNA with Constant Force Axial Optical Tweezers
Published on: October 13, 2011
Compaction dynamics of single DNA molecules under tension
Wen-Bo Fu1, Xiao-Ling Wang, Xing-Hua Zhang
1Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
Journal of the American Chemical Society
|November 23, 2006
Summary
Hexaammine cobalt chloride induces discontinuous DNA compaction and unraveling under specific forces. DNA folding and unfolding involve transitions between metastable states influenced by compaction kinetics.
Area of Science:
- Biophysics
- Molecular Biology
- Materials Science
Background:
- DNA compaction is crucial for genome organization within cells.
- Understanding DNA structural transitions under force is key to molecular mechanics.
Purpose of the Study:
- To investigate the dynamics of DNA compaction induced by hexaammine cobalt chloride.
- To analyze the force-dependent structural transitions of DNA toroids.
Main Methods:
- Utilized transverse magnetic tweezers to apply constant forces to DNA.
- Studied DNA compaction and unraveling dynamics under varying forces (0.5–1.7 pN and >6 pN).
Main Results:
- Observed discontinuous DNA compaction events (approx. 270 nm DNA per event) between 0.5–1.7 pN.
- Found that forces >6 pN induce intermittent, stepwise unraveling of DNA toroids.
- Identified folding/unfolding as transitions between metastable states with a tension-dependent energy barrier.
Conclusions:
- DNA compaction and unraveling are complex processes involving distinct structural states.
- Compaction kinetics and force-dependent energy barriers dictate the degree of DNA ordering in toroids.
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