Synthetic Analogues of Polynucleotides: Interaction of a Polymeric Adenine Derivative with DNA

Abstract

ANALOGUES of polynucleotides in which the naturally occurring bases are partly or completely replaced by analogues have been synthesized in vivo and by enzyme methods^1,2. It appeared to us to be of interest, however, to synthesize polymers soluble in water which could be considered as analogues of polynucleotides in the possession of side chains of purines and/or pyrimidines but in which the backbone would not be composed of sugar residues linked by phosphodiester linkages. Previous work in this laboratory has already shown that a polymer of this type can be formed by copolymerizing 5′-O-acrylyluridine with acrylamide and that this polymer interacts with DNA in solution³; the polymer was obtained by polymerization of a suitable monomer containing a pyrimidine. We now report the synthesis of a similar type of polymer by the linking of a purine derivative and a pre-formed polymer, polyacrylic acid hydrazide⁴. The polymer was treated with the dialdehyde obtained by the periodate oxidation of adenosine, and gave a polymer containing adenine, a fraction of which was found to hybridize with denatured DNA in solution.