Hydrophobic moieties in cations, anions, and alcohols promote the B-to-Z transition in poly[d(G-C)] and poly[d(G-m5C)].

Previous results from our laboratory showed that an increase in the nonpolar alkyl chain length in tetraalkylammonium cations is accompanied by greater efficiency in driving the B-to-Z transition. Analogous effects are observed when the hydrocarbon portion of carboxylate anions and alcohols is increased in size. The more hydrophobic species have a greater ordering effect on the aqueous solvent and promote formation of the less hydrated Z-DNA conformer.