Pre-steady-state kinetic studies establish entecavir 5′-triphosphate as a substrate for HIV-1 reverse transcriptase

Robert A. Domaoal, Moira McMahon, Chloe L. Thio, Christopher M. Bailey, Julian Tirado-Rives, Aleksander Obikhod, Mervi Detorio, Kimberly L. Rapp, Robert F. Siliciano, Raymond F. Schinazi, Karen S. Anderson

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


The novel 2′-deoxyguanosine analog Entecavir (ETV) is a potent inhibitor of hepatitis B virus (HBV) replication and is recommended for treatment in human immunodeficiency virus type 1 (HIV-1) and HBV-co-infected patients because it had been reported that ETV is HBV-specific. Recent clinical observations, however, have suggested that ETV may indeed demonstrate anti-HIV-1 activity. To investigate this question at a molecular level, kinetic studies were used to examine the interaction of 5′-triphosphate form of ETV with wild type (WT) HIV-1 reverse transcriptase (RT) and the nucleoside reverse transcriptase inhibitor-resistant mutation M184V. Using single turnover kinetic assays, we found that HIV-1 WT RT and M184VRT could use the activated ETV triphosphate metabolite as a substrate for incorporation. The mutant displayed a slower incorporation rate, a lower binding affinity, and a lower incorporation efficiency with the 5′-triphosphate form of ETV compared with WTRT, suggesting a kinetic basis for resistance. Our results are supported by cell-based assays in primary human lymphocytes that show inhibition of WT HIV-1 replication by ETV and decreased susceptibility of the HIV-1 containing the M184V mutation. This study has important therapeutic implications as it establishes ETV as an inhibitor for HIV-1 RT and illustrates the mechanism of resistance by the M184V mutant.

Original languageEnglish (US)
Pages (from-to)5452-5459
Number of pages8
JournalJournal of Biological Chemistry
Issue number9
StatePublished - Feb 29 2008

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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