Related Experiment Videos
Conformational changes in the H3 . H4 histone complex. Serological and circular dichroism studies
The Journal of Biological Chemistry
|August 10, 1980
Summary
The study identified distinct structural forms of the histone H3.H4 complex, revealing that changes in salt concentration alter its conformation and expose antigenic sites, suggesting implications for nucleosome dynamics.
Area of Science:
- Biochemistry
- Molecular Biology
- Chromatin Structure
Background:
- The histone H3.H4 complex is a fundamental component of chromatin.
- Understanding its structure is crucial for comprehending DNA organization and gene regulation.
Purpose of the Study:
- To investigate potential structural differences in the histone H3.H4 complex extracted under varying salt conditions.
- To analyze the conformational changes and exposed antigenic sites upon salt dilution.
Main Methods:
- Extraction of calf thymus chromatin under high and low salt conditions.
- Analysis using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).
- Serological analysis and circular dichroism (CD) spectroscopy.
Main Results:
- Two distinct forms of the H3.H4 complex were isolated, composed solely of histones H3 and H4.
- Structural differences were detected between the high and low salt forms via serological and CD analyses.
- Dilution of the high salt complex induced a time-dependent conformational change, reducing alpha-helix content and exposing antigenic sites.
Conclusions:
- The histone H3.H4 complex exists in multiple forms, influenced by ionic strength.
- Conformational flexibility of the H3.H4 complex may play a role in the dynamic nature of nucleosome structure.
- These findings provide insights into the dynamic equilibrium of nucleosome structure in vivo.