Kinetic studies with the non-nucleoside HIV-1 reverse transcriptase inhibitor U-88204E.
The bis(heteroaryl)piperazine U-88204E is a potent inhibitor of HIV-1 reverse transcriptase (RT) and possesses excellent anti-HIV activity in HIV-1-infected lymphocytes grown in tissue culture. Enzymatic kinetic studies of the RNA- and DNA-dependent DNA polymerases of RT were carried out in order to determine whether the inhibitor interacts directly with the template:primer or deoxyribonucleotide triphosphate (dNTP) binding sites of the polymerase. The experimental results were analyzed using steady-state or Briggs-Haldane kinetics, by assuming that the template:primer binds to the enzyme first followed by the dNTP and that the polymerase functions processively. The results of the analysis show that the inhibitor acts as a mixed to noncompetitive inhibitor with respect to both the template:primer and the dNTP binding sites. The potency of U-88204E on the RNA-directed DNA polymerase activity depends on the base composition of the template:primer. The Ki values for the poly(rC):(dG)10-directed reactions were at least 7 times lower than the ones for reactions directed by poly(rA):(dT)10. The inhibitor did not inhibit the RNase H function of HIV-1 RT nor did it impair the RNA-directed DNA polymerase activity of HIV-2 RT. These data thus demonstrate the unique specificity of U-88204E for HIV-1 RT.
Althaus
I W
IW
Upjohn Company, Kalamazoo, Michigan 49001.
Chou
J J
JJ
Gonzales
A J
AJ
Deibel
M R
MR
Chou
K C
KC
Kezdy
F J
FJ
Romero
D L
DL
Palmer
J R
JR
Thomas
R C
RC
Aristoff
P A
PA
D054303:HIV Reverse Transcriptase; D015497:HIV-1 / Q000201:enzymology*; D007211:Indoles / Q000494:pharmacology*; D007700:Kinetics; D008433:Mathematics; D008962:Models, Theoretical; D010879:Piperazines / Q000494:pharmacology*; D011071:Poly T / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors; D018894:Reverse Transcriptase Inhibitors; D016914:Ribonuclease H / Q000037:antagonists & inhibitors*; D013698:Templates, Genetic
D007211:Indoles; D010879:Piperazines; D011994:Recombinant Proteins; D018894:Reverse Transcriptase Inhibitors; C072199:U 88204; D011071:Poly T; D054303:HIV Reverse Transcriptase; D016914:Ribonuclease H