In both proteins, the partitions of the lysine-binding channel are formed by hydrophobic residues that engage in van der Waals interactions with the lysine side chain (Determine 4b,c ). The exception to the rule is the DOT1 family, members of which methylate K79 within the globular area of histone H3 and which are structurally not related to SET-area proteins four - 6 Current work means that SET-area-containing proteins methylate a few proteins in addition to histones (see later)