title: Vinylogous ureas as a novel class of inhibitors of reverse transcriptase-associated ribonuclease H activity.
abstract: High-throughput screening of National Cancer Institute libraries of synthetic and natural compounds identified the vinylogous ureas 2-amino-5,6,7,8-tetrahydro-4 H-cyclohepta[ b]thiophene-3-carboxamide (NSC727447) and N-[3-(aminocarbonyl)-4,5-dimethyl-2-thienyl]-2-furancarboxamide (NSC727448) as inhibitors of the ribonuclease H (RNase H) activity of HIV-1 and HIV-2 reverse transcriptase (RT). A Yonetani-Theorell analysis demonstrated that NSC727447, and the active-site hydroxytropolone RNase H inhibitor beta-thujaplicinol were mutually exclusive in their interaction with the RNase H domain. Mass spectrometric protein footprinting of the NSC727447 binding site indicated that residues Cys280 and Lys281 in helix I of the thumb subdomain of p51 were affected by ligand binding. Although DNA polymerase and pyrophosphorolysis activities of HIV-1 RT were less sensitive to inhibition by NSC727447, protein footprinting indicated that NSC727447 occupied the equivalent region of the p66 thumb. Site-directed mutagenesis using reconstituted p66/p51 heterodimers substituted with natural or non-natural amino acids indicates that altering the p66 RNase H primer grip significantly affects inhibitor sensitivity. NSC727447 thus represents a novel class of RNase H antagonists with a mechanism of action differing from active site, divalent metal-chelating inhibitors that have been reported.
authors.affiliation: HIV Drug Resistance Program, National Cancer Institute, Frederick, Maryland, USA.
authors.forename: Michaela
authors.initials: M
authors.lastname: Wendeler
authors.forename: Hsiu-Fang
authors.initials: HF
authors.lastname: Lee
authors.forename: Alun
authors.initials: A
authors.lastname: Bermingham
authors.forename: Jennifer T
authors.initials: JT
authors.lastname: Miller
authors.forename: Oleg
authors.initials: O
authors.lastname: Chertov
authors.forename: Marion K
authors.initials: MK
authors.lastname: Bona
authors.forename: Noel S
authors.initials: NS
authors.lastname: Baichoo
authors.forename: Maryam
authors.initials: M
authors.lastname: Ehteshami
authors.forename: John
authors.initials: J
authors.lastname: Beutler
authors.forename: Barry R
authors.initials: BR
authors.lastname: O'Keefe
authors.forename: Matthias
authors.initials: M
authors.lastname: Götte
authors.forename: Mamuka
authors.initials: M
authors.lastname: Kvaratskhelia
authors.forename: Stuart
authors.initials: S
authors.lastname: Le Grice
mesh_terms: D001665:Binding Sites; D020650:Combinatorial Chemistry Techniques; D005663:Furans / Q000737:chemistry / Q000494:pharmacology*; D054303:HIV Reverse Transcriptase / Q000037:antagonists & inhibitors* / Q000737:chemistry; D006801:Humans; D018894:Reverse Transcriptase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D054309:Ribonuclease H, Human Immunodeficiency Virus / Q000037:antagonists & inhibitors* / Q000737:chemistry; D013876:Thiophenes / Q000737:chemistry / Q000494:pharmacology*; D014508:Urea / Q000031:analogs & derivatives*
chemical_list: D005663:Furans; C539163:NSC 727447; C539162:NSC 727448; D018894:Reverse Transcriptase Inhibitors; D013876:Thiophenes; D014508:Urea; C514824:reverse transcriptase, Human immunodeficiency virus 1; C072416:reverse transcriptase, Human immunodeficiency virus 2; D054303:HIV Reverse Transcriptase; D054309:Ribonuclease H, Human Immunodeficiency Virus