Protein and nucleic acid methylating enzymes: mechanisms and regulation.

Protein and nucleic acid methylating enzymes are implicated in myriad cellular processes. These enzymes utilize diverse chemical mechanisms ranging from nucleophilic substitution-displacement to a novel radical-based reaction found in bacterial iron-sulfur cluster proteins. Within the cell, methylation activity is governed by interactions with endogenous molecular machinery. Of particular interest are the observations that methylating enzyme activity can be allosterically controlled by regulatory binding partners. Recent advances and emerging trends in the study of methylating enzyme mechanisms and regulation highlight the importance of protein and nucleic acid methylation in cellular physiology and disease.