Phenylethylthiazolylthiourea (PETT) non-nucleoside inhibitors of HIV-1 and HIV-2 reverse transcriptases. Structural and biochemical analyses.
Most non-nucleoside reverse transcriptase (RT) inhibitors are specific for HIV-1 RT and demonstrate minimal inhibition of HIV-2 RT. However, we report that members of the phenylethylthiazolylthiourea (PETT) series of non-nucleoside reverse transcriptase inhibitors showing high potency against HIV-1 RT have varying abilities to inhibit HIV-2 RT. Thus, PETT-1 inhibits HIV-1 RT with an IC(50) of 6 nM but shows only weak inhibition of HIV-2 RT, whereas PETT-2 retains similar potency against HIV-1 RT (IC(50) of 5 nM) and also inhibits HIV-2 RT (IC(50) of 2.2 microM). X-ray crystallographic structure determinations of PETT-1 and PETT-2 in complexes with HIV-1 RT reveal the compounds bind in an overall similar conformation albeit with some differences in their interactions with the protein. To investigate whether PETT-2 could be acting at a different site on HIV-2 RT (e.g. the dNTP or template primer binding site), we compared modes of inhibition for PETT-2 against HIV-1 and HIV-2 RT. PETT-2 was a noncompetitive inhibitor with respect to the dGTP substrate for both HIV-1 and HIV-2 RTs. PETT-2 was also a noncompetitive inhibitor with respect to a poly(rC).(dG) template primer for HIV-2 RT. These results are consistent with PETT-2 binding in corresponding pockets in both HIV-1 and HIV-2 RT with amino acid sequence differences in HIV-2 RT affecting the binding of PETT-2 compared with PETT-1.
Ren
J
J
Structural Biology Division, The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, United Kingdom.
Diprose
J
J
Warren
J
J
Esnouf
R M
RM
Bird
L E
LE
Ikemizu
S
S
Slater
M
M
Milton
J
J
Balzarini
J
J
Stuart
D I
DI
Stammers
D K
DK
D001667:Binding, Competitive; D018360:Crystallography, X-Ray; D017931:DNA Primers / Q000378:metabolism; D003848:Deoxyguanine Nucleotides / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D054303:HIV Reverse Transcriptase / Q000037:antagonists & inhibitors*; D020128:Inhibitory Concentration 50; D007364:Intercalating Agents / Q000494:pharmacology*; D007700:Kinetics; D008956:Models, Chemical; D008958:Models, Molecular; D011485:Protein Binding; D011725:Pyridines / Q000737:chemistry* / Q000494:pharmacology; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism*; D012044:Regression Analysis; D018894:Reverse Transcriptase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D013844:Thiazoles / Q000494:pharmacology*; D013890:Thiourea / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D014230:Triazoles / Q000494:pharmacology*
D017931:DNA Primers; D003848:Deoxyguanine Nucleotides; D007364:Intercalating Agents; C405687:PETT 1; C405688:PETT 2; D011725:Pyridines; D018894:Reverse Transcriptase Inhibitors; D013844:Thiazoles; D014230:Triazoles; C029603:deoxyguanosine triphosphate; C062942:2-phenyl-6-(2'-(4'-(ethoxycarbonyl)thiazolyl))thiazolo(3,2-b)(1,2,4)triazole; C072416:reverse transcriptase, Human immunodeficiency virus 2; D054303:HIV Reverse Transcriptase; D012194:RNA-Directed DNA Polymerase; D013890:Thiourea