Inhibition of HIV-1 Tat-TAR interaction by diphenylfuran derivatives: effects of the terminal basic side chains.
A series of four biscationic diphenylfuran derivatives was used to investigate drug binding to the transactivation response element (TAR) RNA. The drugs, which are active against the Pneumocystis carinii pathogen (PCP), differ by the nature of the terminal basic side chains. Furimidazoline (DB60) is more potent at inhibiting binding of the Tat protein to TAR than furamidine (DB75) and the amidine-substituted analogues DB244 and DB226. In vivo studies using the fusion-induced gene stimulation (FIGS) assay entirely agree with the in vitro gel mobility shift data. The capacity of the drugs to antagonize Tat binding correlates with their RNA binding properties determined by melting temperature and RNase protection experiments. Footprinting studies indicate that the bulge region of TAR provides the identity element for the diphenylfurans. Access of the drugs to the major groove cavity at the pyrimidine bulge depends on the bulk of the alkylamine substituents. Experiments using TAR mutants show that the bulge of TAR is critical for drug binding but also reveal that the fit of the drugs into the major groove cavity of TAR does not involve specific contacts with the highly conserved residue U23 or the C x G26-39 base pair. The binding essentially involves shape recognition. The results are also discussed with respect to the known activity of the drug against PCP which is the major cause of mortality in AIDS patients. This study provides guidelines for future development of TAR-targeted anti-HIV-1 drugs.
Gelus
N
N
INSERM Unité 524 et Laboratoire de Pharmacologie Antitumorale du Centre Oscar Lambret, Lille, France.
Bailly
C
C
Hamy
F
F
Klimkait
T
T
Wilson
W D
WD
Boykin
D W
DW
D000578:Amidines / Q000737:chemistry / Q000494:pharmacology; D019380:Anti-HIV Agents / Q000737:chemistry / Q000494:pharmacology*; D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology; D001483:Base Sequence; D001550:Benzamidines / Q000737:chemistry / Q000494:pharmacology; D018929:Cell Culture Techniques; D018983:DNA Footprinting; D005663:Furans / Q000737:chemistry / Q000494:pharmacology*; D015696:Gene Products, tat / Q000037:antagonists & inhibitors*; D016325:HIV Long Terminal Repeat / Q000187:drug effects*; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics; D007093:Imidazoles / Q000737:chemistry / Q000494:pharmacology; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D011485:Protein Binding / Q000187:drug effects; D012367:RNA, Viral / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D054322:tat Gene Products, Human Immunodeficiency Virus
D000578:Amidines; D019380:Anti-HIV Agents; D000935:Antifungal Agents; D001550:Benzamidines; C120947:DB 226; C120948:DB 244; D005663:Furans; D015696:Gene Products, tat; D007093:Imidazoles; D012367:RNA, Viral; C120946:furimidazoline; D054322:tat Gene Products, Human Immunodeficiency Virus; C033286:furamidine