[Spectroscopic study of interactions between nucleic acid bases and amino acid esters in dimethylsulfoxide]

Interactions between nucleic acid bases (A, T, U. C) and some amino acid esters have been investigated by IR and UV spectroscopies in dimethylsulfoxide. The stability of associates of amino acid esters with the bases was established to form the following sequence: C greater than A much greater than U, T. The obtained data show that stability of complexes between the bases and amino acid esters decreases in the order: His greater than Met greater than Arg greater than Lys greater than Ser greater than or approximately Gly. The association is apparently realized through formation of two H-bonds, one of them involving the carbonyl group of amino acid, and another--its side chain.