Models of interaction between nucleic acids and proteins. Hydrogen bonding of arginine with nucleic acid bases, phosphate groups and carboxylic acids.

Complex formation between the side chain of arginine and nucleic acid bases has been investigated by proton magnetic resonance in dimethylsulfoxide. Simultaneous formation of two hydrogen bonds leads to a selectivity of arginine interaction towards cytosine and guanine. A comparison is made of the interaction of arginine side chain with nucleic acid bases, phosphate and carboxylate anions. It is shown that interaction between carboxylate and arginine is stronger than between phosphate and arginine. These results are discussed with respect to the selective recognition of nucleic acid bases by arginine side chains and by the arginyl-glutamyl ion pair which could form in proteins interacting with nucleic acids.