title: Peptide aldehyde inhibitors of hepatitis A virus 3C proteinase.
abstract: Picornaviral 3C proteinases are a group of closely related thiol proteinases responsible for processing of the viral polyprotein into its component proteins. These proteinases adopt a chymotrypsin-like fold [Allaire et al. (1994) Nature 369, 72-77; Matthews et al. (1994) Cell 77, 761-771] and a display an active-site configuration like those of the serine proteinases. Peptide-aldehydes based on the preferred peptide substrates for hepatitis A virus (HAV) 3C proteinase were synthesized by reduction of a thioester precursor. Acetyl-Leu-Ala-Ala-(N,N'-dimethylglutaminal) was found to be a reversible, slow-binding inhibitor for HAV 3C with a Ki* of (4.2 +/- 0.8) x 10(-8) M. This inhibitor showed 50-fold less activity against the highly homologous human rhinovirus (strain 14) 3C proteinase, whose peptide substrate specificity is slightly different, suggesting a high degree of selectivity. NMR spectrometry of the adduct of the 13C-labeled inhibitor with the HAV-3C proteinase indicate that a thiohemiacetal is formed between the enzyme and the aldehyde carbon as previously noted for peptide-aldehyde inhibitors of papain [Lewis & Wolfenden (1977) Biochemistry 16,4890-4894; Gamcsik et al. (1983) J. Am. Chem. Soc. 105, 6324-6325]. The adduct can also be observed by electrospray mass spectrometry.
authors.affiliation: Protein Engineering Network of Centres of Excellence Department of Chemistry, University of Alberta, Edmonton, Canada.
authors.forename: B A
authors.initials: BA
authors.lastname: Malcolm
authors.forename: C
authors.initials: C
authors.lastname: Lowe
authors.forename: S
authors.initials: S
authors.lastname: Shechosky
authors.forename: R T
authors.initials: RT
authors.lastname: McKay
authors.forename: C C
authors.initials: CC
authors.lastname: Yang
authors.forename: V J
authors.initials: VJ
authors.lastname: Shah
authors.forename: R J
authors.initials: RJ
authors.lastname: Simon
authors.forename: J C
authors.initials: JC
authors.lastname: Vederas
authors.forename: D V
authors.initials: DV
authors.lastname: Santi
mesh_terms: D000086042:3C Viral Proteases; D000595:Amino Acid Sequence; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D011480:Protease Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D014764:Viral Proteins
chemical_list: D009842:Oligopeptides; D011480:Protease Inhibitors; D014764:Viral Proteins; C094351:acetyl-leucyl-alanyl-alanyl-(N,N'-dimethylglutaminal); D003546:Cysteine Endopeptidases; D000086042:3C Viral Proteases