Functional characterization of chimeric reverse transcriptases with polypeptide subunits of highly divergent HIV-1 group M and O strains

J Biol Chem. 2001 Jul 20;276(29):27470-9. doi: 10.1074/jbc.M104342200. Epub 2001 May 15.


Human immunodeficiency virus (HIV)-1 strains have been divided into three groups: main (M), outlier (O), and non-M non-O (N). Biochemical analyses of HIV-1 reverse transcriptase (RT) have been performed predominantly with enzymes derived from HIV-1 group M:subtype B laboratory strains. This study was designed to optimize the expression and to characterize the enzymatic properties of HIV-1 group O RTs as well as chimeric RTs composed of group M and O p66 and p51 subunits. The DNA-dependent DNA polymerase activity on a short heteropolymeric template-primer was similar with all enzymes, i.e. the HIV-1 group O and M and chimeric RTs. Our data revealed that the 51-kDa subunit in the chimeric heterodimer p66(M:B)/p51(O) confers increased heterodimer stability and partial resistance to non-nucleoside RT inhibitors. Chimeric RTs (p66(M:B)/p51(O) and p66(O)/p51(M:B)) were unable to initiate reverse transcription from tRNA(3)(Lys) using HIV-1 group O or group M:subtype B RNA templates. In contrast, HIV-1 group O and M RTs supported (-)-strand DNA synthesis from tRNA(3)(Lys) hybridized to any of their corresponding HIV-1 RNA templates. HIV-2 RT could not initiate reverse transcription on tRNA(3)(Lys)-primed HIV-1 genomic RNA. These findings suggest that the initiation event is conserved between HIV-1 groups, but not HIV types.

Publication types

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

MeSH terms

  • Base Sequence
  • DNA Primers
  • HIV Reverse Transcriptase / chemistry
  • HIV Reverse Transcriptase / isolation & purification
  • HIV Reverse Transcriptase / metabolism*
  • HIV-1 / genetics
  • HIV-2 / genetics
  • Humans
  • Models, Molecular
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Protein Conformation
  • RNA, Viral / chemistry
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / isolation & purification
  • Recombinant Fusion Proteins / metabolism*
  • Reverse Transcriptase Inhibitors / pharmacology
  • Sequence Homology, Nucleic Acid


  • DNA Primers
  • RNA, Viral
  • Recombinant Fusion Proteins
  • Reverse Transcriptase Inhibitors
  • HIV Reverse Transcriptase

Associated data

  • GENBANK/AF068947
  • GENBANK/AF378083