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Stretching Short Sequences of DNA with Constant Force Axial Optical Tweezers
Published on: October 13, 2011
Probing persistence in DNA curvature properties with atomic force microscopy
J Moukhtar1, E Fontaine, C Faivre-Moskalenko
1Laboratoires Joliot Curie (USR 3010) et de Physique (UMR 5672), Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon cedex 07, France.
Physical Review Letters
|May 16, 2007
Summary
Genomic DNA
Area of Science:
- Biophysics
- Molecular Biology
- Genetics
Background:
- The wormlike chain model describes DNA flexibility.
- Genomic DNA exhibits intrinsic curvature disorder.
- Long-range correlations (LRC) can influence DNA structure.
Purpose of the Study:
- To extend the wormlike chain model to include LRC in DNA's intrinsic curvature.
- To investigate the impact of LRC on DNA persistence length.
- To differentiate between sequence-induced curvature and increased flexibility in human DNA.
Main Methods:
- Developed a mean-field extension of the wormlike chain model.
- Incorporated long-range correlations (LRC) into the model.
- Utilized atomic force microscopy (AFM) imaging.
- Performed DNA simulations.
- Compared viral and human DNA fragments.
Main Results:
- Stronger LRC in DNA's intrinsic curvature correlates with decreased persistence length.
- Human DNA fragments showed a reduced persistence length compared to viral DNA.
- Simulations and AFM imaging supported the findings.
Conclusions:
- The observed decrease in human DNA persistence length is primarily due to sequence-induced large-scale intrinsic curvature.
- Increased DNA flexibility is a less likely explanation for the reduced persistence length.
