Left-handed DNA: from Synthetic Polymers to Chromosomes

Abstract

The interconversions between right-handed (R) and left-handed (L) helical conformations of DNA have been assessed by spectroscopic, electrophoretic, immunochemical, and enzymatic techniques. We have screened salt and solvent conditions which facilitate these transitions, as well as certain chemical modifications of the bases and backbone of defined synthetic polynucleotides. These include major and minor groove substituents as well as phosphoro- thioate analogues of selected phosphodiester bonds. We have established: From these and other results we propose that Z*-DNA may have important structural- functional roles in the cell.