SUV39H1, the first identified histone lysine methyltransferase in human, is 
involved in chromatin modification and gene regulation. SUV39H1 contains a 
chromodomain in its N-terminus, which potentially plays a role in methyl-lysine 
recognition and SUV39H1 targeting. In this study, the structure of the 
chromodomain of human SUV39H1 was determined by X-ray crystallography. The 
SUV39H1 chromodomain displays a generally conserved structure fold compared with 
other solved chromodomains. However, different from other chromodomains, the 
SUV39H1 chromodomain possesses a much longer helix at its C-terminus. 
Furthermore, the SUV39H1 chromodomain was shown to recognize histone H3K9me2/3 
specifically.