CONFORMATIONAL STUDY OF THE DIPEPTIDE ARGINYLGLUTAMIC ACID AND OF ITS COMPLEX WITH NUCLEIC BASES

Proton and 13C magnetic resonance spectra are reported for Ac-Arg-Glu-NHEt, Boc-Arg-Glu-NHEt, and protected Arg and Glu peptides. An intramolecular complex with two hydrogen bonds is found between side chains of arginine and glutamic acid. In all protected peptides containing a carboxylate group, a hydrogen bond is found between COO- and the peptidic NH (Glu). Replacing the carboxylate group (COO-) by the acid function (COOH) leads to the vanishing of the intramolecular hydrogen bond. NMR investigation of the interaction of the dipeptide with nucleic acid bases has shown that only guanine forms a strong intermolecular complex. Guanine forms a complex with two hydrogen bonds with carboxylate groups and disrupts the intramolecular Arg-Glu complex. No strong interaction was seen between bases and arginine. © 1979, American Chemical Society. All rights reserved.