The roles of proteins that have methylated arginines have been identified in many cases, and include RNA processing, signal transduction, DNA repair, cardiovascular disease and cancer. The specific interactions caused by methylation itself, however, are not fully established.

We have been investigating whether one electron reduction of the cationic side chain may play a role in methylation. Our models in calculations were N-methylated triaminomethyl radicals. Here we present and compare the structures and energies of models for reduced, symmetrically and anti-symmetrically dimethylated arginine side chains. The calculations were performed with the B3LYP density functional, using cc-pVTZ and aug-cc-pVTZ basis sets.