This peptide is histone H3 with acetylation at Lys4. It is biotinylated through a C-terminal GGK linker. This post-translationally modified histone peptide is found in humans, Tetrahymena thermophila, Schizosaccharomyces pombe , and mice. Acetylation at Lys4 is controlled by Mst1. This peptide acts as a chromodomain switch by weakening the interaction between Chp1 and the H3K9 methylated tail, thus facilitating binding of HP1 proteins. Provided at >95% peptide purity, this peptide was dissolved in distilled water at 1 mg/ml and re-lyophilized to powder form.