Abstract
Using the interaction of polyacrylic anhydride with uridine or Nβacetyl derivatives of adenosine, cytidine, and guanosine, the waterβsoluble copolymers, polyacryloylnucleosides, were obtained. The acryloylnucleoside units to acrylic acid units ratio in the copolymer was usually about 1:20. The attaching of nucleosides to the polymer occurs mostly through the 5β²βhydroxyl group of the sugar.
The prominent feature of all polyacryloylnucleosides obtained is their fibrous structure at an ionic strength 0.2 and neutral pH. At concentrations <200 ΞΌg/ml the separate strands with a length of 0.2β1.0 ΞΌ and diameter of 30β40 Γ
are distinguishable. Evidently they are formed by side association of two molecules of copolymer or by folding of one molecule on itself. At higher concentrations branched multistranded structures are formed. In the same conditions polyacrylic acid alone does not form the fibrous structures.
Heating of polyacryloylnucleoside solutions at 100Β°C and fast cooling in ice water, or raising of the pH to 12 turned the stranded structures to coils. After annealing or neutralization the stranded structures reformed. These transformations are similar to those which occur with nucleic acids. The results show that the fibrous structure of the copolymers depends on the hydrogen bonds formed by purine and/or pyrimidine bases.