The phenylmethylthiazolylthiourea nonnucleoside reverse transcriptase (RT) inhibitor MSK-076 selects for a resistance mutation in the active site of human immunodeficiency virus type 2 RT

J Virol. 2004 Jul;78(14):7427-37. doi: 10.1128/JVI.78.14.7427-7437.2004.

Abstract

The phenylmethylthiazolylthiourea (PETT) derivative MSK-076 shows, besides high potency against human immunodeficiency virus type 1 (HIV-1), marked activity against HIV-2 (50% effective concentration, 0.63 microM) in cell culture. Time-of-addition experiments pointed to HIV-2 reverse transcriptase (RT) as the target of action of MSK-076. Recombinant HIV-2 RT was inhibited by MSK-076 at 23 microM. As was also found for HIV-1 RT, MSK-076 inhibited HIV-2 RT in a noncompetitive manner with respect to dGTP and poly(rC).oligo(dG) as the substrate and template-primer, respectively. MSK-076 selected for A101P and G112E mutations in HIV-2 RT and for K101E, Y181C, and G190R mutations in HIV-1 RT. The selected mutated strains of HIV-2 were fully resistant to MSK-076, and the mutant HIV-2 RT enzymes into which the A101P and/or G112E mutation was introduced by site-directed mutagenesis showed more than 50-fold resistance to MSK-076. Mapping of the resistance mutations to the HIV-2 RT structure ascertained that A101P is located at a position equivalent to the nonnucleoside RT inhibitor (NNRTI)-binding site of HIV-1 RT. G112E, however, is distal to the putative NNRTI-binding site in HIV-2 RT but close to the active site, implying a novel molecular mode of action and mechanism of resistance. Our findings have important implications for the development of new NNRTIs with pronounced activity against a wider range of lentiviruses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Anti-HIV Agents / pharmacology*
  • Cells, Cultured
  • Cytopathogenic Effect, Viral
  • Drug Resistance, Viral*
  • HIV Reverse Transcriptase
  • HIV-1 / drug effects
  • HIV-2 / drug effects*
  • HIV-2 / enzymology
  • HIV-2 / genetics
  • Humans
  • Microbial Sensitivity Tests
  • Models, Molecular
  • Molecular Sequence Data
  • Mutation
  • RNA-Directed DNA Polymerase / chemistry
  • RNA-Directed DNA Polymerase / drug effects*
  • RNA-Directed DNA Polymerase / genetics
  • Reverse Transcriptase Inhibitors / pharmacology*
  • Thiazoles / chemistry
  • Thiazoles / pharmacology*
  • Triazoles / chemistry
  • Triazoles / pharmacology*

Substances

  • Anti-HIV Agents
  • Reverse Transcriptase Inhibitors
  • Thiazoles
  • Triazoles
  • 2-phenyl-6-(2'-(4'-(ethoxycarbonyl)thiazolyl))thiazolo(3,2-b)(1,2,4)triazole
  • reverse transcriptase, Human immunodeficiency virus 2
  • HIV Reverse Transcriptase
  • RNA-Directed DNA Polymerase