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Micromechanical Study of Hyperacetylated Nucleosomes Using Single Molecule Transverse Magnetic Tweezers
Santosh Gaire1, Roberto L Fabian1, Raghabendra Adhikari2
1Department of Physics and Vitreous State Laboratory, The Catholic University of America, Washington, DC 20064, USA.
International Journal of Molecular Sciences
|April 13, 2023
Summary
Histone post-translational modifications (PTMs) influence DNA-protein complex structure. Hyperacetylated histones, studied using magnetic tweezers, showed distinct nucleosome disassembly forces compared to native histones.
Area of Science:
- Molecular Biology
- Genomics
- Biophysics
Background:
- Nucleosomes, DNA-protein complexes, are crucial for genome function and must disassemble for essential processes.
- Histone post-translational modifications (PTMs) regulate nucleosome structure, but mechanisms are unclear.
Purpose of the Study:
- Investigate the mechanical properties of hyperacetylated nucleosomes using single-molecule micromanipulation.
- Compare the behavior of hyperacetylated nucleosomes with native histones under force.
Main Methods:
- Utilized transverse magnetic tweezers for single-molecule force measurements.
- Formed DNA-protein complexes with hyperacetylated histones and lambda-DNA.
- Applied controlled forces (2-80 pN) to measure nucleosome unbinding and DNA extension changes.
Main Results:
- Hyperacetylated nucleosomes exhibited quantized extension changes (~50 nm steps) under tension.
- Unbinding force for hyperacetylated nucleosomes (~2.5 pN) was similar to native histones.
- Hyperacetylated nucleosomes disassembled at significantly lower forces (<6 pN) compared to native histones.
Conclusions:
- Hyperacetylation alters nucleosome disassembly dynamics under force.
- Single-molecule force spectroscopy reveals distinct mechanical behaviors influenced by histone PTMs.
