POLYMERS CONTAINING 2'-O-METHYLNUCLEOTIDES .2. SYNTHESIS OF HETEROPOLYMERS

Heteropolymers containing 2′-O-methyladenylic acid, 2′-O-methylcytidylic acid, and nonmethylated nucleotides have been synthesized with polynucleotide phosphorylase from their corresponding nucleoside 5′-diphosphates. The distribution of 2′-O-methylnucleotides in these polymers was not completely random but occurred in pairs. The frequency of this paired incorporation indicates some form of cooperative polymerization of 2′-O-methylnucleotides in the presence of nonmethylated nucleotides. The addition of dimethyl sulfoxide to the polymerization reaction enhanced the random incorporation of 2′-O-methyladenosine 5′-diphosphate in the presence of cytidine 5′-diphosphate but had little effect on the incorporation of 2′-O-methylcytidine 5′-diphosphate in the presence of uridine 5′-diphosphate. Certain restrictions on the formation of heteropolymers by Micrococcus lysodeikticus polynucleotide phosphorylase were noted. 2′-O-Methyladenosine 5′-diphosphate formed heteropolymers with cytidine 5′diphosphate and uridine 5′-diphosphate but not guanosine 5′-diphosphate and adenosine 5′-diphosphate. 2′-O-Methylcytidine 5′-diphosphate formed heteropolymers with uridine 5′-diphosphate but would not form a homopolymer nor would it form heteropolymers with cytidine 5′-diphosphate, adenosine 5′-diphosphate, or guanosine 5′-diphosphate. A heteropolymer containing 2′-O-methyladenosine, 2′-O-methylcytidine, and uridine was synthesized from the corresponding nucleoside 5′-diphosphates. © 1969, American Chemical Society. All rights reserved.