Crystal Structures of Clinically Relevant Lys103Asn/Tyr181Cys Double Mutant HIV-1 Reverse Transcriptase in Complexes with ATP and Non-nucleoside Inhibitor HBY 097

Kalyan Das, Stefan G. Sarafianos, Arthur D. Clark, Paul L. Boyer, Stephen H. Hughes, Eddy Arnold

Research output: Contribution to journalArticlepeer-review

71 Scopus citations

Abstract

Lys103Asn and Tyr181Cys are the two mutations frequently observed in patients exposed to various non-nucleoside reverse transcriptase inhibitor drugs (NNRTIs). Human immunodeficiency virus (HIV) strains containing both reverse transcriptase (RT) mutations are resistant to all of the approved NNRTI drugs. We have determined crystal structures of Lys103Asn/Tyr181Cys mutant HIV-1 RT with and without a bound non-nucleoside inhibitor (HBY 097, (S)-4-isopropoxycarbonyl-6-methoxy-3-(methylthio-methyl)-3,4-dihydroquin oxalin-2(1H)-thione) at 3.0 Å and 2.5 Å resolution, respectively. The structure of the double mutant RT/HBY 097 complex shows a rearrangement of the isopropoxycarbonyl group of HBY 097 compared to its binding with wild-type RT. HBY 097 makes a hydrogen bond with the thiol group of Cys181 that helps the drug retain potency against the Tyr181Cys mutation. The structure of the unliganded double mutant HIV-1 RT showed that Lys103Asn mutation facilitates coordination of a sodium ion with Lys101 O, Asn103 N and Oδ1, Tyr188 Oη, and two water molecules. The formation of the binding pocket requires the removal of the sodium ion. Although the RT alone and the RT/HBY 097 complex were crystallized in the presence of ATP, only the RT has an ATP coordinated with two Mn2+ at the polymerase active site. The metal coordination mimics a reaction intermediate state in which complete octahedral coordination was observed for both metal ions. Asp186 coordinates at an axial position whereas the carboxylates of Asp110 and Asp185 are in the planes of coordination of both metal ions. The structures provide evidence that NNRTIs restrict the flexibility of the YMDD loop and prevent the catalytic aspartate residues from adopting their metal-binding conformations.

Original languageEnglish (US)
Pages (from-to)77-89
Number of pages13
JournalJournal of molecular biology
Volume365
Issue number1
DOIs
StatePublished - Jan 5 2007

All Science Journal Classification (ASJC) codes

  • Structural Biology
  • Molecular Biology

Keywords

  • conformational flexibility
  • drug design
  • drug resistance
  • polymerase

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