BINDING OF POLYRIBONUCLEOTIDES TO SINGLE-STRANDED TP-84 DEOXYRIBONUCLEIC ACID

The presence of specific nucleotide clusters on the complementary deoxyribonucleic acid strands of bacteriophage TP-84 has been investigated by the polyribonucleotide binding technique of Szybalski and coworkers. Complex formation between denatured deoxyribonucleic acid and homoribopolymers is detected by a density shift in a CsCl density gradient. The complementary strands of denatured TP-84 deoxyribonucleic acid have been isolated and shown to be distinct in several properties (buoyant density in CsCl, nucleotide base composition, annealing of phage-induced ribonucleic acid exclusively to the heavy strand). The lightstrand forms complexes with poly U, and poly C indicating the presence of nucleotide sequences of dA, and dG, respectively. The heavy-strand interacts with poly G, poly (I, G), (suggesting dC sequences), and poly X suggesting dA and/or dT sequences. Normal base-pairing considerations indicate anomalous binding in some cases. Although poly X should complex with both deoxyribonucleic acid strands it does not. Likewise, since poly U binds the light strand then poly A should complex with the complementary deoxyribonucleic acid strand but does not. The accessibility of certain nucleotide clusters to react with homoribopolymers may be a topological feature of the specific deoxyribonucleic acid strand. © 1969, American Chemical Society. All rights reserved.