Interaction of nucleic acids and glycans

Spectrophotometric analysis and dot-hybridization have shown that amylose forms complexes with polypyrimidines (poly dC), while polyuronides form complexes with polypurines (poly dA). In addition, the formation of complexes genomic thymus DNA-hyaluronic acid has been observed. A certain role in the mechanism of NA-polysaccharide interactions can be played by the links between purines and the carboxylic group of hexuronic acid residue, as well as between pyrimidines and the hydroxymethyl group of hexose residue. The quantum-chemical calculations showed that, between nitric bases of DNA and the carboxyl groups of hexuronic acids or the hydroxymethyl group of hexose, hydrogen bonds can be formed the energy of which is comparable with that in the complementary AT and CG pairs. The strength of these bonds is unequal: carboxyl groups form stronger hydrogen bonds with purines and weaker bonds with pyrimidines. The hydroxymethyl group, on the contrary, forms stronger hydrogen bonds with pyrimidines and weaker bonds with purines. The quantum-chemical modeling shows that, in the complementary pairs purin-uronic acid and pyrimidine-hexose, hydrogen bonds are produced that form a binary chain nucleic acid-polysaccharide. The data obtained suggest the existence of template synthesis of GAG polysaccharide fragments with the participation of NA.