Molecular basis for the enantioselectivity of HIV-1 reverse transcriptase: role of the 3'-hydroxyl group of the L-(beta)-ribose in chiral discrimination between D- and L-enantiomers of deoxy- and dideoxy-nucleoside triphosphate analogs

Nucleic Acids Res. 1999 Feb 15;27(4):972-8. doi: 10.1093/nar/27.4.972.


In order to identify the basis for the relaxed enantio-selectivity of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) and to evaluate possible cross-resistance patterns between L-nucleoside-, D-nucleoside- and non-nucleoside RT inhibitors, to be utilised in anti-HIV-1 combination therapy, we applied an in vitro approach based on the utilisation of six recom-binant HIV-1 RT mutants containing single amino acid substitutions known to confer Nevirapine resistance in treated patients. The mutants were compared on different RNA/DNA and DNA/DNA substrates to the wild type (wt) enzyme for their sensitivity towards inhibition by the D- and L-enantiomers of 2'-deoxy- and 2',3'-dideoxynucleoside triphosphate analogs. The results showed that the 3'-hydroxyl group of the L-(beta)-2'-deoxyribose moiety caused an unfavourable steric hindrance with critic residues in the HIV-1 RT active site and this steric barrier was increased by the Y181I mutation. Elimination of the 3'-hydroxyl group removed this hindrance and significantly improved binding to the HIV-1 RT wt and to the mutants. These results demonstrate the critical role of both the tyrosine 181 of RT and the 3'-position of the sugar ring, in chiral discrimination between D- and L-nucleoside triphosphates. Moreover, they provide an important rationale for the combination of D- and L-(beta)-dideoxynucleoside analogs with non-nucleoside RT inhibitors in anti-HIV chemotherapy, since non-nucleosideinhibitors resistance mutations did not confer cross-resistance to dideoxynucleoside analogs.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Anti-HIV Agents / metabolism*
  • Anti-HIV Agents / pharmacology
  • Carbohydrates
  • Catalysis
  • DNA / biosynthesis
  • Deoxycytosine Nucleotides / metabolism
  • Deoxycytosine Nucleotides / pharmacology
  • Deoxyribonucleosides / metabolism
  • Deoxyribonucleosides / pharmacology
  • Dideoxynucleosides / metabolism*
  • Dideoxynucleosides / pharmacology
  • Dideoxynucleotides
  • Drug Resistance, Microbial
  • HIV Reverse Transcriptase / antagonists & inhibitors
  • HIV Reverse Transcriptase / chemistry
  • HIV Reverse Transcriptase / genetics
  • HIV Reverse Transcriptase / metabolism*
  • Humans
  • Hydroxyl Radical*
  • Isoleucine
  • Kinetics
  • Nevirapine / metabolism
  • Nevirapine / pharmacology
  • Recombinant Fusion Proteins / antagonists & inhibitors
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Reverse Transcriptase Inhibitors / metabolism*
  • Reverse Transcriptase Inhibitors / pharmacology
  • Ribose / chemistry
  • Ribose / metabolism*
  • Templates, Genetic
  • Thymine Nucleotides / metabolism
  • Thymine Nucleotides / pharmacology
  • Tyrosine
  • Zidovudine / analogs & derivatives
  • Zidovudine / metabolism
  • Zidovudine / pharmacology


  • Anti-HIV Agents
  • Carbohydrates
  • Deoxycytosine Nucleotides
  • Deoxyribonucleosides
  • Dideoxynucleosides
  • Dideoxynucleotides
  • Recombinant Fusion Proteins
  • Reverse Transcriptase Inhibitors
  • Thymine Nucleotides
  • Isoleucine
  • 2'-deoxycytidine 5'-triphosphate
  • Hydroxyl Radical
  • 3'-fluorothymidine-5'-triphosphate
  • Tyrosine
  • Zidovudine
  • Ribose
  • zidovudine triphosphate
  • DNA
  • Nevirapine
  • HIV Reverse Transcriptase
  • thymidine 5'-triphosphate