Hydrophilic Polymers of Ordered Conformation— Nucleic Acid Models

Nucleic acids contain severa' characteristic structural features: a chiral center adjacent to the base, a stereoregular, hydrophilic poly(phosphate-ribose) backbone which is negatively charged at neutral pH, and a helical secondary structure arising from conformational preferences enforced by base-stacking. We have prepared and studied several synthetic polynucleotide analogs having linear poly(ethylenimine), poly(vinylamine), and poly(dehydroalanine) backbones containing chiral nucleic acid base pendant groups attached through amide bonds. This amide bond increases structural order through its partial double bond character, resulting in restricted rotation of the pendant. Through study of model compounds and from UV, CD, and NMR spectroscopy, we have obtained considerable evidence for polynucleotide-like ordered conformations in these polymers. In addition, several of the polymers have shown antiviral activity in cell culture tests.