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Stretching Short Sequences of DNA with Constant Force Axial Optical Tweezers
Published on: October 13, 2011
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Force-dependent persistence length of DNA-intercalator complexes measured in single molecule stretching experiments
R F Bazoni1, C H M Lima, E B Ramos
1Laboratório de Física Biológica, Departamento de Física, Universidade Federal de Viçosa. Viçosa, Minas Gerais, Brazil. marcios.rocha@ufv.br.
Soft Matter
|April 28, 2015
Summary
Stretching DNA-intercalator complexes with optical tweezers revealed force-dependent persistence length, unlike bare DNA. This suggests stretching may induce partial DNA denaturation, affecting mechanical properties.
Area of Science:
- Biophysics
- Molecular Biology
- Materials Science
Background:
- DNA mechanical properties are crucial for biological functions.
- DNA-intercalator complexes exhibit altered mechanical behaviors.
- Understanding force-dependent mechanics is key to DNA-protein interactions.
Purpose of the Study:
- Investigate the impact of applied forces on DNA-intercalator complex mechanics.
- Determine if DNA-intercalator persistence length is force-dependent.
- Explore the underlying physicochemical mechanisms.
Main Methods:
- Single-molecule stretching experiments using optical tweezers.
- Utilized adjustable trap stiffness for precise force control.
- Analyzed two distinct DNA-intercalator complexes.
Main Results:
- DNA-intercalator complexes showed a strong force-dependent persistence length.
- This force dependency was observed even in the low-force entropic regime.
- Bare DNA molecules did not exhibit this force-dependent behavior.
Conclusions:
- Stretching force influences the mechanical response of DNA-intercalator complexes.
- Partial DNA denaturation, induced by stretching, is a proposed mechanism.
- Altered persistence length in complexes is linked to force-induced denaturation.
