Synthesis of ε-N-propionyl-, ε-N-butyryl-, and ε-N-crotonyl-lysine containing histone H3 using the pyrrolysine system.

Recently new lysine modifications were detected in histones and other proteins. Using the pyrrolysine amber suppression system we genetically inserted three of the newamino acids epsilon-N-propionyl-, epsilon-N-butyryl-, and epsilon-N-crotonyl-lysine site specifically into histone H3. The lysine at position 9 (H3 K9), which is known to be highly modified in chromatin, was replaced by these unnatural amino acids.