Histone acetylation is a modification where an acetyl group is transferred to lysine residues in histone tails. This process is catalyzed by HATs. Acetylation neutralizes the positive charge on histones, reducing their affinity for the negatively charged DNA. This results in a more relaxed chromatin structure, which is associated with active transcription. Conversely, HDACs remove acetyl groups, leading to chromatin condensation and transcriptional repression.
