A protein sequence alignment of the SET domains of a number of representative histone lysine methyltransferases (HKMT) grouped based on their histone-lysine specificity. The exception to the rule is the DOT1 family, members of which methylate K79 in the globular area of histone H3 and that are structurally not related to SET-domain proteins 4 - 6 Latest work means that SET-domain-containing proteins methylate a number of proteins along with histones (see later)