Simultaneous mutations at Tyr‐181 and Tyr‐188 in HIV‐1 reverse transcriptase prevents inhibition of RNA‐dependent DNA polymerase activity by the bisheteroarylpiperazine (BHAP) U‐90152s

The replacement of either Tyr-181 or Tyr-188 of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) by the corresponding HIV-2 RT amino acids Ile-181 or Leu-188 is known to result in active mutant enzymes (Y181I; Y188L) with virtual loss of sensitivity towards three structural classes of nonnucleoside RT inhibitors; L-697,661, nevirapine, and TIBO R82913. The bisheteroarylpiperazine (BHAP) U-90152S, a highly specific inhibitor (IC50, 0.29 +/- 0.01 microM) of HIV-1 RT, inhibited the recombinant Y181I and Y188L HIV-1 RT mutants with IC50 values of 3.6 +/- 0.15 microM and 0.71 +/- 0.02 microM, respectively. Construction and in vitro analysis of double mutants Y181I/Y188L and Y181C/Y188L of HIV-1 RT showed > 150-fold resistance to U-90152S. An HIV-2 RT mutant containing amino acids 176-190 from HIV-1 RT acquired full sensitivity to U-90152S (IC50, 0.26 +/- 0.01 microM). It is concluded that simultaneous mutations at Tyr-181 and Tyr-188 of HIV-1 RT promotes resistance to U-90152S.