title: Substrate mimicry: HIV-1 reverse transcriptase recognizes 6-modified-3'-azido-2',3'-dideoxyguanosine-5'-triphosphates as adenosine analogs.
abstract: β-D-3'-Azido-2',3'-dideoxyguanosine (3'-azido-ddG) is a potent inhibitor of HIV-1 replication with a superior resistance profile to zidovudine. Recently, we identified five novel 6-modified-3'-azido-ddG analogs that exhibit similar or superior anti-HIV-1 activity compared to 3'-azido-ddG in primary cells. To gain insight into their structure-activity-resistance relationships, we synthesized their triphosphate (TP) forms and assessed their ability to inhibit HIV-1 reverse transcriptase (RT). Steady-state and pre-steady-state kinetic experiments show that the 6-modified-3'-azido-ddGTP analogs act as adenosine rather than guanosine mimetics in DNA synthesis reactions. The order of potency of the TP analogs against wild-type RT was: 3'-azido-2,6-diaminopurine >3'-azido-6-chloropurine; 3'-azido-6-N-allylaminopurine > 2-amino-6-N,N-dimethylaminopurine; 2-amino-6-methoxypurine. Molecular modeling studies reveal unique hydrogen-bonding interactions between the nucleotide analogs and the template thymine base in the active site of RT. Surprisingly, the structure-activity relationship of the analogs differed in HIV-1 RT ATP-mediated excision assays of their monophosphate forms, suggesting that it may be possible to rationally design a modified base analog that is efficiently incorporated by RT but serves as a poor substrate for ATP-mediated excision reactions. Overall, these studies identify a promising strategy to design novel nucleoside analogs that exert profound antiviral activity against both WT and drug-resistant HIV-1.
authors.affiliation: Department of Medicine, Division of Infectious Diseases, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Herman
authors.forename: Raymond F
authors.initials: RF
authors.lastname: Schinazi
authors.forename: Hong-wang
authors.initials: HW
authors.lastname: Zhang
authors.forename: James H
authors.initials: JH
authors.lastname: Nettles
authors.forename: Richard
authors.initials: R
authors.lastname: Stanton
authors.forename: Mervi
authors.initials: M
authors.lastname: Detorio
authors.forename: Aleksandr
authors.initials: A
authors.lastname: Obikhod
authors.forename: Ugo
authors.initials: U
authors.lastname: Pradère
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Coats
authors.forename: John W
authors.initials: JW
authors.lastname: Mellors
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sluis-Cremer
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives; D000255:Adenosine Triphosphate / Q000737:chemistry; D019380:Anti-HIV Agents / Q000737:chemistry* / Q000378:metabolism; D020134:Catalytic Domain; D015224:Dideoxynucleosides / Q000737:chemistry*; D054306:Dideoxynucleotides / Q000737:chemistry* / Q000378:metabolism; D054303:HIV Reverse Transcriptase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D018716:Molecular Mimicry; D009154:Mutation; D018894:Reverse Transcriptase Inhibitors / Q000737:chemistry* / Q000378:metabolism
chemical_list: D019380:Anti-HIV Agents; D015224:Dideoxynucleosides; D054306:Dideoxynucleotides; D018894:Reverse Transcriptase Inhibitors; C051073:3'-azido-2',3'-dideoxyguanosine; D000255:Adenosine Triphosphate; C514824:reverse transcriptase, Human immunodeficiency virus 1; D054303:HIV Reverse Transcriptase; D000241:Adenosine