title: E-64 analogues as inhibitors of cathepsin B. On the role of the absolute configuration of the epoxysuccinyl group.
abstract: A series of trans-epoxysuccinyl-peptide derivatives based on the natural inhibitor E-64 were synthesized in the (2R,3R) and (2S,3S) configuration in order to analyze the role of the stereochemistry of this residue in dictating inhibitory potency and selectivity for cysteine proteases. We confirmed that binding of E-64 like trans-epoxysuccinyl compounds is remarkably favored by the (2S,3S) configuration, but we also found that CA030-type compounds are stronger inhibitors in the (2R,3R) configuration than the related diastereomers. Consequently, the structural requirements for exploiting both the S and S' subsites are not additive and a structure-based design of bis-peptidyl derivatives of trans-epoxysuccinic acid to increase selective inhibition becomes even more difficult. Additional contrasting effects were observed for the pH optima required in the electrostatic interactions at the S and S' subsites.
authors.affiliation: Max-Planck-Institut für Biochemie, Martinsried, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Schaschke
authors.forename: I
authors.initials: I
authors.lastname: Assfalg-Machleidt
authors.forename: W
authors.initials: W
authors.lastname: Machleidt
authors.forename: D
authors.initials: D
authors.lastname: Turk
authors.forename: L
authors.initials: L
authors.lastname: Moroder
mesh_terms: D002401:Cathepsin B / Q000037:antagonists & inhibitors*; D018360:Crystallography, X-Ray; D015853:Cysteine Proteinase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007930:Leucine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D012492:Salts; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013237:Stereoisomerism
chemical_list: D015853:Cysteine Proteinase Inhibitors; D012492:Salts; D002401:Cathepsin B; D007930:Leucine; C024974:E 64