Peptide aldehyde inhibitors of hepatitis A virus 3C proteinase.
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.
Malcolm
B A
BA
Protein Engineering Network of Centres of Excellence Department of Chemistry, University of Alberta, Edmonton, Canada.
Lowe
C
C
Shechosky
S
S
McKay
R T
RT
Yang
C C
CC
Shah
V J
VJ
Simon
R J
RJ
Vederas
J C
JC
Santi
D V
DV
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
D009842:Oligopeptides; D011480:Protease Inhibitors; D014764:Viral Proteins; C094351:acetyl-leucyl-alanyl-alanyl-(N,N'-dimethylglutaminal); D003546:Cysteine Endopeptidases; D000086042:3C Viral Proteases