Physical properties of poly (3,N4-ethenocytidylic acid)

Homopolymers of etheno CMP have been prepared by the action of polyribonucleotide phosphorylase upon etheno CDP. At alkaline pH the optical properties are consistent with a structure consisting of partially helical single-stranded chains whose helical regions are stabilized by base stacking. At acid pH the degree of helicity increases markedly. The degree of cooperativity displayed by the helix leads to coil transition induced by pH or temperature is less than for the case of polyribocytidylic acid. In the presence of acridine orange the alkaline form develops a strong extrinsic CD spectrum.