Human spleen histone H3. Isolation and amino acid sequence

Area of Science:

• Biochemistry
• Molecular Biology
• Evolutionary Biology

Background:

• Histone H3 is a core component of eukaryotic chromatin.
• Previous studies characterized human spleen histone H2B and H2A.
• Understanding histone H3 sequence variations is crucial for evolutionary studies.

Purpose of the Study:

• To determine the amino acid sequence of human spleen histone H3.
• To compare human H3 with other eukaryotic H3 sequences.
• To investigate histone evolution through sequence analysis.

Main Methods:

• Purification of histone H3 fraction using Bio-Gel P-10 chromatography.
• Enzymatic digestion of histone H3 with Clostripain, trypsin, and chymotrypsin.
• Peptide sequencing via Edman degradation.

Main Results:

• The human spleen histone H3 sequence consists of 135 amino acid residues.
• It is nearly identical to calf thymus H3, with five substitutions identified.
• Three methylated lysines and two acetylated lysines were detected, indicating post-translational modifications.
• Sequence variations suggest the presence of at least two human H3 variants.

Conclusions:

• Human spleen histone H3 exhibits high conservation across eukaryotes.
• Identified substitutions and modifications offer insights into histone H3 evolution.
• The findings support the presence of multiple histone H3 variants in humans.