title: HIV-1 reverse transcriptase: inhibition by 2',5'-oligoadenylates.
abstract: 2',5'-Oligoadenylates (2-5A) and derivatives are noncompetitive inhibitors of primer/HIV-1 reverse transcriptase complex formation. The mechanism and specificity of this inhibitory action of 2-5A and 2-5A derivatives have been evaluated with 2-5A molecules modified in ribosyl moiety, chain length, extent of 5'-phosphorylation, and 2',5'-phosphodiester linkage. UV covalent cross-linking of preformed complexes of p66/p66 homodimer or p66/p51 heterodimer recombinant HIV-1 reverse transcriptase and the primer analog pd(T)16 allowed analysis of the initial step in HIV-1 reverse transcriptase-catalyzed DNA synthesis. Utilizing this primer binding assay, it is demonstrated that 2-5A and 2-5A derivatives inhibit the binding of pd(T)16 to HIV-1 reverse transcriptase. This inhibition is specific for the 2',5'-internucleotide linkage in that the corresponding 3',5'-adenylate derivatives do not exhibit inhibitory activity. Enhanced inhibitory properties were observed following modifications of the 2-5A molecule which result in an increase in hydrophobicity. Replacement of the D-ribosyl moiety of 2-5A with the 3'-deoxyribosyl moiety increased the inhibition of primer/HIV-1 reverse transcriptase complex formation 15-20%. 2',5'-Phosphorothioate substitution yielded the most effective inhibitors, with Ki's of 7-13 microM. In all cases, inhibition of primer/HIV-1 reverse transcriptase complex formation showed a preference for the 5'-triphosphate moiety. Nonphosphorylated derivatives were not inhibitory; 5'-monophosphate derivatives exhibited little or no inhibition. The inhibition of primer binding to HIV-1 reverse transcriptase correlated well with the inhibition of DNA-directed DNA synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Biochemistry, Temple University School of Medicine, Philadelphia, Pennsylvania 19140.
authors.forename: R W
authors.initials: RW
authors.lastname: Sobol
authors.forename: W L
authors.initials: WL
authors.lastname: Fisher
authors.forename: N L
authors.initials: NL
authors.lastname: Reichenbach
authors.forename: A
authors.initials: A
authors.lastname: Kumar
authors.forename: W A
authors.initials: WA
authors.lastname: Beard
authors.forename: S H
authors.initials: SH
authors.lastname: Wilson
authors.forename: R
authors.initials: R
authors.lastname: Charubala
authors.forename: W
authors.initials: W
authors.lastname: Pfleiderer
authors.forename: R J
authors.initials: RJ
authors.lastname: Suhadolnik
mesh_terms: D000227:Adenine Nucleotides / Q000494:pharmacology*; D000998:Antiviral Agents / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis / Q000187:drug effects; D054303:HIV Reverse Transcriptase; D015497:HIV-1 / Q000201:enzymology*; D009843:Oligoribonucleotides / Q000494:pharmacology*; D010766:Phosphorylation; D010777:Photochemistry; D018894:Reverse Transcriptase Inhibitors; D013936:Thymidine / Q000378:metabolism
chemical_list: D000227:Adenine Nucleotides; D000998:Antiviral Agents; D009843:Oligoribonucleotides; D018894:Reverse Transcriptase Inhibitors; C023505:2',5'-oligoadenylate; D004247:DNA; D054303:HIV Reverse Transcriptase; D013936:Thymidine