title: Design and synthesis of substrate-based peptidomimetic human immunodeficiency virus protease inhibitors containing the hydroxymethylcarbonyl isostere.
abstract: The human immunodeficiency (HIV) codes for an aspartic protease known to be essential for retroviral maturation and replication. The HIV protease can recognize Phe-Pro and Tyr-Pro sequences as the virus-specific cleavage site. These features provided a basis for the rational design of selective HIV protease-targeted drugs for the treatment of acquired immunodeficiency syndrome (AIDS). HIV protease is formed from two identical 99 amino acid peptides. We replaced the two Cys residues by L-Ala to synthesize [Ala67,95]-HIV-1 protease by the solid phase method and then prepared [Tyr6,42, Nle36,46, (NHCH2COSCH2CO)51-52, Ala67,95] HIV-1 protease (NY-5 isolate) using the thioester chemical ligation method. Based on the substrate transition state, we designed and synthesized a novel class of HIV protease inhibitors containing an unnatural amino acid, (2S, 3S)-3-amino-2-hydroxy-4-phenylbutyric acid, named allophenylnorstatine (Apns) with a hydroxymethylcarbonyl (HMC) isostere. Among them, the conformationally constrained tripeptide kynostatin (KNI)-272 (iQoa-Mta-Apns-Thz-NHBut) was a highly selective and superpotent HIV protease inhibitor (Ki = 0.0055 nM). KNI-272 exhibited potent antiviral activities against both AZT-sensitive and -insensitive clinical HIV-1 isolates as well as HIV-2 with low cytotoxicity. After i.d. administration, bioavailability of KNI-272 was 42.3% in rats. Also, KNI-272 exhibited in vivo anti-HIV activities in human PBMC-SCID mice. The x-ray crystallography and molecular modeling studies showed that the HMC group in KNI-272 interacted excellently with the aspartic acid carboxyl groups of HIV protease active site in the essentially same hydrogen-bonding mode as the transition state. This result implies that the HMC isostere is an ideal transition-state mimic and contributes to the high activity of KNI-272.
authors.affiliation: Department of Medicinal Chemistry, Kyoto Pharmaceutical University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kiso
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000188:drug therapy; D000595:Amino Acid Sequence; D000818:Animals; D000998:Antiviral Agents / Q000138:chemical synthesis* / Q000494:pharmacology; D001665:Binding Sites; D015195:Drug Design; D016333:HIV Protease / Q000737:chemistry; D017320:HIV Protease Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000627:therapeutic use; D006801:Humans; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D010654:Phenylbutyrates / Q000032:analysis
chemical_list: D000998:Antiviral Agents; D017320:HIV Protease Inhibitors; D009842:Oligopeptides; D010654:Phenylbutyrates; C034940:3-amino-2-hydroxy-4-phenylbutanoic acid; D016333:HIV Protease; C077822:kynostatin 272