Probing structure/function relationships of HIV-1 reverse transcriptase with styrene oxide N2-guanine adducts

J Biol Chem. 1997 Mar 28;272(13):8525-30. doi: 10.1074/jbc.272.13.8525.


Details of the interactions between the human immunodeficiency virus (HIV-1) reverse transcriptase and substrate DNA were probed both by introducing site-specific and stereospecific modifications into DNA and by altering the structure of potential critical residues in the polymerase. Unadducted 11-mer DNAs and 11-mer DNAs containing R and S enantiomers of styrene oxide at N2-guanine were ligated with two additional oligonucleotides to create 63-mers that served as templates for HIV-1 reverse transcriptase replication. Oligonucleotides that primed synthesis 5 bases 3' to the adducts could be extended up to 1 base 3' and opposite the lesion. However, when the positions of the 3'-OH of the priming oligonucleotides were placed 1, 2, 3, 4, 5, and 6 bases downstream of the styrene oxide guanine adducts, replication was initiated, only to be blocked after incorporating 4, 5, 6, and 7 bases beyond the lesion. The sites of this adduct-induced termination corresponded to the position of the DNA where alpha-helix H makes contact with the DNA minor groove, 3-5 bases upstream of the growing 3' end. In addition, mutants of the polymerase in alpha-helix H (W266A and G262A) alter the termination probabilities caused by these DNA adducts, suggesting that alpha-helix H is a sensitive monitor of modifications in the minor groove of newly synthesized template-primer DNA several bases distal to the 3'-OH.

Publication types

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

MeSH terms

  • Base Sequence
  • DNA / metabolism
  • DNA Adducts / metabolism*
  • DNA Replication*
  • Epoxy Compounds / metabolism*
  • Guanine / metabolism*
  • HIV Reverse Transcriptase / genetics
  • HIV Reverse Transcriptase / metabolism*
  • Isomerism
  • Models, Molecular
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Templates, Genetic


  • DNA Adducts
  • Epoxy Compounds
  • Guanine
  • DNA
  • styrene oxide
  • HIV Reverse Transcriptase