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.

Original publication

DOI

10.1074/jbc.275.8.5633

Type

Journal article

Journal

The Journal of biological chemistry

Publication Date

02/2000

Volume

275

Pages

5633 - 5639

Addresses

Structural Biology Division, The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, United Kingdom.

Keywords

Thiourea, Triazoles, Pyridines, Thiazoles, RNA-Directed DNA Polymerase, Deoxyguanine Nucleotides, DNA Primers, Reverse Transcriptase Inhibitors, Intercalating Agents, Crystallography, X-Ray, Regression Analysis, Inhibitory Concentration 50, Binding, Competitive, Protein Binding, Dose-Response Relationship, Drug, Kinetics, Models, Chemical, Models, Molecular, HIV Reverse Transcriptase