H3K56ac is the synthesized histone H3 peptide corresponding to residues within 1-135 of human histone H3 with acetylation K56 modification. H3K56ac is a covalent modification known as a mark of newly replicated chromatin as well as replication-independent histone replacement. H3K56ac is important for chromatin remodeling and serves as a marker of new nucleosomes during DNA replication but its role in the cell cycle is debated. Lysine 56 is located at the amino-terminal αN-helix and close to the site where the DNA enters and exits the nucleosome. Due to its location on the lateral surface of the nucleosome, which is close to the DNA entry/exit site and interacts with DNA. The studies on yeast might not apply to the mammals. Mammalian cells do not express HATs with high specificity to K56. Sirtuins can catalyze the removal of the acetyl group from K56. H3K56ac levels are elevated in cancer and pluripotent cells. TRIM66 reads unmodified H3R2K4 and H3K56ac to respond to DNA damage.
