title: Physicochemical properties of phosphorothioate oligodeoxynucleotides.
abstract: We have recently shown that phosphorothioate (PS) oligodeoxynucleotide (ODN) analogs, unlike their normal congeners, exhibit significant anti-HIV activity (Matsukura et al., (1987) Proc. Natl. Acad. Sci. USA 84, 7706-7710). We now report the syntheses, melting temperatures (Tm), and nuclease susceptibilities of a series of phosphorothioate ODN analogs. These include all-PS duplexes, duplexes with one normal chain and the other chain either all-PS, or end-capped with several PS groups at both 3' and 5' ends. The DNase susceptibilities of the S-ODNs are much less than the normal phosphodiesters, but by contrast duplexes of poly-rA with S-dT40 are much more susceptible to RNase H digestion. The Tm's for AT base pairs of S-ODNs are significantly depressed relative to normals, while GC base pairs show much less Tm depression. The Tm's of S-dT oligomers with poly-rA are reduced relative to the duplexes with normal dA oligomers. These results have significance for the biological properties of these analogs as anti-message inhibitors of gene expression, and provide a rational basis for the S-dC/G sequences as potential effective anti-AIDS agents.
authors.affiliation: Clinical Pharmacology Branch, National Cancer Institute, Bethesda, MD 20892.
authors.forename: C A
authors.initials: CA
authors.lastname: Stein
authors.forename: C
authors.initials: C
authors.lastname: Subasinghe
authors.forename: K
authors.initials: K
authors.lastname: Shinozuka
authors.forename: J S
authors.initials: JS
authors.lastname: Cohen
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004720:Endonucleases / Q000378:metabolism; D004722:Endoribonucleases / Q000378:metabolism; D009691:Nucleic Acid Denaturation; D009708:Nucleotidases / Q000378:metabolism; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis* / Q000378:metabolism; D043264:Phosphodiesterase I; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D016914:Ribonuclease H; D015719:Single-Strand Specific DNA and RNA Endonucleases; D013696:Temperature; D013873:Thionucleotides / Q000138:chemical synthesis* / Q000378:metabolism
chemical_list: D009838:Oligodeoxyribonucleotides; D013873:Thionucleotides; D004720:Endonucleases; D004722:Endoribonucleases; D016914:Ribonuclease H; D009708:Nucleotidases; D015719:Single-Strand Specific DNA and RNA Endonucleases; D010727:Phosphoric Diester Hydrolases; D043264:Phosphodiesterase I