Related Experiment Videos
Structure of polyubiquitinated histone H2A
1Department of Biochemistry, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
Biochemistry
|February 7, 1989
Summary
Polyubiquitinated histone H2A in trout liver features ubiquitin chains linked via isopeptide bonds. These chains attach to lysine 119 on histone H2A, revealing a key structural arrangement.
Area of Science:
- Biochemistry
- Molecular Biology
- Chromatin Structure
Background:
- Recent studies showed trout liver histones H2A, H2B, and H2A.Z undergo polyubiquitination.
- Polyubiquitination is a post-translational modification affecting protein function and stability.
Purpose of the Study:
- To determine the arrangement of ubiquitin molecules within polyubiquitinated histone H2A.
- To elucidate the specific linkage and attachment sites of ubiquitin chains on histone H2A.
Main Methods:
- Trout liver chromatin, with histone H1 removed, was digested using Staphylococcus aureus (V8 strain) protease.
- Proteolytic digestion products were analyzed using two-dimensional gel electrophoresis.
- Ubiquitinated peptides were detected using anti-ubiquitin IgG.
Main Results:
- V8 protease degraded histone H2A and ubiquitinated H2A (uH2A) at similar rates, cleaving the Glu121-Lys122 peptide bond.
- Histone H2A and uH2A were cleaved into cH2A and cuH2A species, respectively.
- The major arrangement of ubiquitin in polyubiquitinated H2A involves a chain of ubiquitin molecules linked by isopeptide bonds to lysine 119 of histone H2A.
Conclusions:
- Polyubiquitinated histone H2A exhibits a specific structural organization with ubiquitin chains attached to Lys119.
- This finding provides insight into the structural basis of histone H2A polyubiquitination and its potential functional implications in chromatin.