A Synthetic HIV-1 Protease Inhibitor with Antiviral Activity Arrests HIV-Like Particle Maturation

Abstract

A synthetic peptidemimetic substrate of the human immunodeficiency virus 1 (HIV-1) protease with a nonhydrolyzable pseudodipeptidyl insert at the protease cleavage site was prepared. The peptide U-81749 inhibited recombinant HIV-1 protease in vitro (inhibition constant Ki of 70 nanomolar) and HIV-1 replication in human peripheral blood lymphocytes (inhibitory concentration IC50 of 0.1 to 1 micromolar). Moreover, 10 micromolar concentrations of U-81749 significantly inhibited proteolysis of the HIV-1 gag polyprotein (p55) to the mature viral structural proteins p24 and p17 in cells infected with a recombinant vaccinia virus expressing the HIV-1 gag-pol genes. The HIV-1 like particles released from inhibitor-treated cells contained almost exclusively p55 and other gag precursors, but not p24. Incubation of HIV-like particles recovered from drug-treated cultures in drug-free medium indicated that inhibition of p55 proteolysis was at least partially reversible, suggesting that U-81749 was present within the particles.

Targeting structural flexibility in HIV-1 protease inhibitor binding

“…Deletion mutagenesis of the gene encoding HIV PR resulted in the production of virus particles that had an immature morphology and were noninfectious [6]. This was confirmed by mutation of the active site aspartic acids [7] and later, by chemical inhibition with protease inhibitors [8]. These seminal experiments provided conclusive proof that viral protease is essential for the life cycle of HIV and highlighted this enzyme as an important target for the design of specific antiviral agents.…”

REVIEW : Recent advances in developing web-servers for predicting protein attributes

“…One is to target the HIV (human immunodeficiency virus) reverse transcriptase (see, e.g., [165][166][167][168][169][170][171]); the other is to design HIV protease inhibitors [128,136,138,139,[172][173][174].…”

Sequence‐Specific Resonance Assignments of the 1H‐NMR Spectra and Structural Characterization in Solution of the HIV‐1 Transframe Protein p6*

“…Prior to budding, Gag and Gag-Pol polyproteins assemble at the cytoplasmic membrane. Premature processing by a HIV protease activated too early prevents packing of the cleavage products into the virions, whereas inhibition of the protease results in immature and non-infectious particles (Facke et al, 1993;Gottlinger et al, 1989;Kaplan et al, 1993;Kohl et al, 1988;Krausslich, 1991;McQuade et al, 1990;Meek et al, 1990). There is evidence from in vitro transcription-translation assays that the frame shift protein p6* inhibits the processing activity of the HIV protease by blocking the active site in a manner similar to the pepsinogen N-terminal prosegment (James and Sielecki, 1986;Partin et al, 1991 ;Zybarth and Carter, 1995).…”