AcdK

AcdK is a non-natural amino acid and a precursor of allysine. It can be site-specifically incorporated into target proteins in Escherichia coli using an amber codon suppression strategy. AcdK enables site-specific lysine dimethylation or monomethylation modifications of target proteins. It can synthesize site-specific lysine-methylated variants of histone H3 and p53, which are useful for studying the substrate specificity and catalytic functions of epigenetic enzymes.

AcdK (0.5 mM) is efficiently and site-specifically incorporated into the D134 position of sfGFP in E.coli BL21 (DE3) cells. Subsequent biocompatible reactions quantitatively transform it to sfGFP with site-specific dimethylation of lysine at D134. AcdK (2 mM) is also efficiently and site-specifically incorporated into histone H3 at positions K4, K9, or K36 in E.coli BL21 (DE3) cells, and further reactions convert it into site-specifically dimethylated histone H3 variants. Additionally, AcdK can be integrated efficiently and site-specifically into the K372 position of p53 in E.coli BL21 (DE3) cells, enabling its conversion into p53 with site-specific mono- or dimethylation of lysine at K372. This modification can directly increase the acetylation level of p53 at K120, catalyzed by Tip60, by 2.5 to 3 times.