Aza-peptidyl Michael acceptor and epoxide inhibitors--potent and selective inhibitors of Schistosoma mansoni and Ixodes ricinus legumains (asparaginyl endopeptidases).
Aza-peptide Michael acceptors and epoxides with the general structure of YCO-Ala-Ala-AAsn-trans-CH horizontal lineCHCOR and YCO-Ala-Ala-AAsn-EP-COR, respectively, are shown to be potent inhibitors of asparaginyl endopeptidases (legumains) from the bloodfluke, Schistosoma mansoni (SmAE), and the hard tick, Ixodes ricinus (IrAE). Structure-activity relationships (SARs) were determined for a set of 41 aza-peptide Michael acceptors and eight aza-peptide epoxides. Both enzymes prefer disubstituted amides to monosubstituted amides in the P1' position, and potency increased as we increased the hydrophobicity of the inhibitor in this position. Extending the inhibitor to P5 resulted in increased potency, especially against IrAE, and both enzymes prefer small over large hydrophobic residues at P2. Aza-peptide Michael acceptor inhibitors are more potent than aza-peptide epoxide inhibitors, and for some of these compounds, second-order inhibiton rate constants are the fastest yet discovered. Given the central functions of these enzymes in both parasites, the data presented here may facilitate the eventual design of selective antiparasitic drugs.
School of Chemistry and Biochemistry, Petit Institute for Bioscience and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA.
Asli
A
Ovat
Fanuel
F
Muindi
Crystal
C
Fagan
Michelle
M
Brouner
Elizabeth
E
Hansell
Jan
J
Dvorák
Daniel
D
Sojka
Petr
P
Kopácek
James H
JH
McKerrow
Conor R
CR
Caffrey
James C
JC
Powers
D000595:Amino Acid Sequence; D000818:Animals; D001372:Aza Compounds / Q000737:chemistry*; D001682:Biological Availability; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D015195:Drug Design; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D004852:Epoxy Compounds / Q000737:chemistry*; D018884:Ixodes / Q000201:enzymology*; D007700:Kinetics; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology*; D012550:Schistosoma mansoni / Q000201:enzymology*; D000099240:Asparaginyl Endopeptidase
D001372:Aza Compounds; D003546:Cysteine Endopeptidases; D004791:Enzyme Inhibitors; D004852:Epoxy Compounds; D009842:Oligopeptides; D000099240:Asparaginyl Endopeptidase