Structures of HIV-1 RT-RNA/DNA ternary complexes with dATP and nevirapine reveal conformational flexibility of RNA/DNA: insights into requirements for RNase H cleavage

Nucleic Acids Res. 2014 Jul;42(12):8125-37. doi: 10.1093/nar/gku487. Epub 2014 May 31.


In synthesizing a double-stranded DNA from viral RNA, HIV-1 reverse transcriptase (RT) generates an RNA/DNA intermediate. RT also degrades the RNA strand and synthesizes the second DNA strand. The RNase H active site of RT functions as a nuclease to cleave the RNA strand; however, the structural basis for endonucleolytic cleavage of the RNA strand remains elusive. Here we report crystal structures of RT-RNA/DNA-dATP and RT-RNA/DNA-nevirapine (NVP) ternary complexes at 2.5 and 2.9 Å resolution, respectively. The polymerase region of RT-RNA/DNA-dATP complex resembles DNA/DNA ternary complexes apart from additional interactions of 2'-OH groups of the RNA strand. The conformation and binding of RNA/DNA deviates significantly after the seventh nucleotide versus a DNA/DNA substrate. Binding of NVP slides the RNA/DNA non-uniformly over RT, and the RNA strand moves closer to the RNase H active site. Two additional structures, one containing a gapped RNA and another a bulged RNA, reveal that conformational changes of an RNA/DNA and increased interactions with the RNase H domain, including the interaction of a 2'-OH with N474, help to position the RNA nearer to the active site. The structures and existing biochemical data suggest a nucleic acid conformation-induced mechanism for guiding cleavage of the RNA strand.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Anti-HIV Agents / chemistry*
  • DNA, Viral / chemistry*
  • DNA, Viral / metabolism
  • Deoxyadenine Nucleotides / chemistry*
  • HIV Reverse Transcriptase / chemistry*
  • Models, Molecular
  • Nevirapine / chemistry*
  • Nucleic Acid Conformation
  • RNA, Viral / chemistry*
  • RNA, Viral / metabolism
  • Reverse Transcriptase Inhibitors / chemistry*
  • Ribonuclease H / metabolism


  • Anti-HIV Agents
  • DNA, Viral
  • Deoxyadenine Nucleotides
  • RNA, Viral
  • Reverse Transcriptase Inhibitors
  • Nevirapine
  • reverse transcriptase, Human immunodeficiency virus 1
  • HIV Reverse Transcriptase
  • Ribonuclease H
  • 2'-deoxyadenosine triphosphate