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Histone phosphorylation in native chromatin induces local structural changes as probed by electric birefringence
Journal of Molecular Biology
|November 20, 1985
Summary
Histone phosphorylation, specifically of H3 and H5, alters chromatin structure by relaxing its conformation and increasing fiber flexibility. This suggests phosphorylation impacts histone-DNA interactions, potentially affecting chromatin condensation.
Area of Science:
- Molecular Biology
- Chromatin Structure
- Epigenetics
Background:
- Histones are crucial for organizing DNA into chromatin.
- Phosphorylation is a key post-translational modification affecting protein function.
- The impact of histone phosphorylation on chromatin structure remains incompletely understood.
Purpose of the Study:
- To investigate how histone phosphorylation affects chromatin structure and transitions.
- To elucidate the role of specific histone modifications in chromatin organization.
Main Methods:
- Electron microscopy
- Sedimentation velocity
- Circular dichroism
- Electric birefringence and relaxation time measurements
Main Results:
- In vitro phosphorylation of histones H3 and H5 in chicken erythrocyte chromatin was achieved.
- Electron microscopy revealed structural relaxation in phosphorylated chromatin at low ionic strength.
- Electric birefringence indicated increased fiber flexibility and local structural changes, suggesting altered histone-DNA interactions.
Conclusions:
- Histone H3 and H5 phosphorylation induces local structural changes in chromatin, increasing fiber flexibility.
- Phosphorylation may weaken histone H3-DNA interactions, potentially influencing chromatin condensation.
- Findings suggest a role for H3 phosphorylation in regulating chromatin superstructure.