Structure-based design of nonpeptide inhibitors specific for the human immunodeficiency virus 1 protease.

Abstract

By using a structure-based computer-assisted search, we have found a butyrophenone derivative that is a selective inhibitor of the human immunodeficiency virus 1 (HIV-1) protease. The computer program creates a negative image of the active site cavity using the crystal structure of the HIV-1 protease. This image was compared for steric complementarity with 10,000 molecules of the Cambridge Crystallographic Database. One of the most interesting candidates identified was bromperidol. Haloperidol, a closely related compound and known antipsychotic agent, was chosen for testing. Haloperidol inhibits the HIV-1 and HIV-2 proteases in a concentration-dependent fashion with a K1 of -100 ILM. It is highly selective, having little inhibitory effect on pepsin activity and no effect on renin at concentrations as high as 5 mM. The hydroxy derivative of haloperidol has a similar effect on HIV-1 protease but a lower potency against the HIV-2 enzyme. Both haloperidol and its hydroxy derivative showed activity against maturation of viral polypeptides in a cell assay system. Although this discovery holds promise for the generation of nonpeptide protease inhibitors, we caution that the serum concentrations of haloperidol in normal use as an antipsychotic agent are <10 ng/ml (0.03 IAM). Thus, concentrations required to inhibit the HIV-1 protease are >1000 times higher than the concentrations normally used. Haloperidol is highly toxic at elevated doses and can be life-threatening. Haloperidol is not useful as a treatment for AIDS but may be a useful lead compound for the development of an antiviral pharmaceutical.

Synthetic “interface” peptides alter dimeric assembly of the HIV 1 and 2 proteases

“…Following a 30-min incubation at 37 "C, the reactions were quenched by addition of acetonitrile and TFA. The products were analyzed by HPLC as previously described (DesJarlais et al, 1990). Similar assay conditions were used for the determination of inhibitory constants (Dixon plots) except that substrate 1 was used in a range of 0.05-2 mM.…”

“…These reactions were also monitored by HPLC fractionation. All the kinetic data were analyzed by the method of least squares using the Enzfitter computer software (DesJarlais et al, 1990).…”

“…Recombinant human renin was assayed as described previously (DesJarlais et al, 1990) using angiotensinogen 1-14 as substrate.…”

Flexible ligand docking using conformational ensembles

“…In such situations, docking programs have predicted the structures of molecular complexes (Janin, 1995;Shoichet & Kuntz, 1996;Strynadka et al, 1996a) and discovered novel ligands (Bartlett et al, 1989;DesJarlais et al, 1990;Bodian et al, 1993;Ring et al, 1993;Rutenber et al, 1993;. However, as conformational change becomes more significant, the accuracy of rigid body docking programs diminishes.…”

“…Despite important successes (Bartlett et al, 1989;DesJarlais et al, 1990;Bodian et al, 1993;Olson & Goodsell, 1993;Ring et al, 1993;Rutenber et al, 1993;Strynadka et al, 1996a), molecular docking faces several methodological problems. These include predicting the relative binding affinities of different possible complexes, identifying binding sites on receptors, and allowing for molecular flexibility in the docking event.…”