BRAINCAKEHistone Acetylation
Histone acetylation is the addition of acetyl groups (-COCH3) to histone proteins. It is an epigenetic modification that usually switches genes on.
Why histones hold DNA tightly
Histones have 'tails' that stick out from the nucleosome. These tails contain many amino acids called lysine, which carry a positive charge. DNA is negatively charged because of its phosphate groups, so histones and DNA attract each other strongly and the chromatin is tightly packed.
Adding acetyl groups
Enzymes called histone acetyltransferases (HATs) add acetyl groups to the lysines in the histone tails. This:
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More in Gene Expression
- Epigenetics
- DNA Methylation
- DNA Demethylation
- Euchromatin and Heterochromatin
- Histone Methylation
- non-Coding RNA
- siRNA
- Cell Differentiation
All 39 lessons in Gene Expression · All Edexcel A-level Biology topics