Mechanism of resistance of human immunodeficiency virus type 1 to 2',3'-dideoxyinosine

Proc Natl Acad Sci U S A. 1993 Jul 1;90(13):6135-9. doi: 10.1073/pnas.90.13.6135.


A molecular clone containing the wild-type reverse transcriptase (RT) coding region of human immunodeficiency virus type 1 (HIV-1) was constructed, and site-directed mutagenesis was used to introduce mutations--Leu74-->Val (L74V), T215Y, and the combination L74V/T215Y--into the RT coding region. The proteins were purified by immunoaffinity chromatography. Assays were performed with mutant and wild-type RT to determine substrate and inhibitor specificity. All three mutant enzymes catalyzed the incorporation of substrate 2'-deoxynucleoside 5'-triphosphates (dNTPs) as efficiently as wild-type HIV-1 RT. Small changes were observed in the Km values for dNTPs with all three mutant enzymes, while more significant changes were noted in sensitivity to nucleoside 5'-triphosphate analogues that inhibit the enzyme activity. Results suggest that altered substrate recognition by the HIV-1 RT is involved in the mechanism of resistance.

MeSH terms

  • Base Sequence
  • Cloning, Molecular
  • Deoxyribonucleotides / metabolism
  • Didanosine / pharmacology*
  • Drug Resistance, Microbial
  • HIV Reverse Transcriptase
  • HIV-1 / drug effects*
  • HIV-1 / enzymology
  • HIV-1 / genetics
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Mutation
  • RNA-Directed DNA Polymerase / genetics
  • RNA-Directed DNA Polymerase / metabolism*
  • Reverse Transcriptase Inhibitors


  • Deoxyribonucleotides
  • Reverse Transcriptase Inhibitors
  • HIV Reverse Transcriptase
  • RNA-Directed DNA Polymerase
  • Didanosine