Fig. 1

Mechanism and structures of histone methyltransferases (HMT). a Mechanism of catalysis for HMTs. Upon binding to a HMT, the histone lysine NH₂ group undergoes a nucleophilic attack to the methyl group of SAM, producing a methylated lysine and SAH; b The overall structure of DOT1L-SAM complex (PDB: 1NW3) and the close-up view of its active site; c The overall structure of G9a-SAH complex (PDB: 3K5K) and the close-up view of its active site. SAM/SAH are shown as tube models with their C atoms in green