Biopolymers and cell. 1989. Volume 5. № 6. 21 - 25

I. V. Kondratyuk, 1. N. Kolomiets, S. A. Samoilenko, N. V. Zheltovsky

A STUDY OF COMPLEXES BETWEEN CYTOSINE AND AMINO ACID CARBOXYLIC GROUP BY NMR SPEGTRQSOOPY

Summary

    It has been shown by UV spectroscopy that of all the nucleotide bases only cytosine interacts with undissociated aminn acid carboxylic group in DMSO solution. H-bonded complexes of cytosine with some amino acid 'N-acyl derivatives (N-formyl aspartic acid, N-acetyl aspartic acid, a-methyl ester of N-acetyl aspartic acid, N-acetyl glutamic acid, N-formyl glycine) were studied by the PMR spectroscopy. It has been determined by 13C NMR spectroscopy that while complexing cytosine is protonated at N3 atom by carboxylic group proton. It was shown that in triple complex N-formyl aspartic acid: cytosine: 9-methyl guanine amino acid carboxylic group, binding to cytosine, loosens H-bonds inside the base pair.