title: Synthesis and SAR of thrombin inhibitors incorporating a novel 4-amino-morpholinone sscaffold: analysis of X-ray crystal structure of enzyme inhibitor complex.
abstract: A 4-amino-2-carboxymethyl-3-morpholinone structural motif derived from malic acid has been used to mimic d-Phe-Pro in the thrombin inhibiting tripeptide d-Phe-Pro-Arg. The arginine in D-Phe-Pro-Arg was replaced by the more rigid P1 truncated p-amidinobenzylamine (Pab). These new thrombin inhibitors were used to probe the inhibitor binding site of alpha-thrombin. The best candidate in this series of thrombin inhibitors exhibits an in vitro IC50 of 0.130 microM. Interestingly, the stereochemistry of the 4-amino-2-carboxymethyl-3-morpholinone motif is reversed for the most active compounds compared to that of a previously reported 2-carboxymethyl-3-morpholinone series. The X-ray crystal structure of the lead inhibitor cocrystallized with alpha-thrombin is discussed.
authors.affiliation: Department of Chemistry, Linköping University, S-581 83 Linköping, Sweden.
authors.forename: Jonas W
authors.initials: JW
authors.lastname: Nilsson
authors.forename: Ingemar
authors.initials: I
authors.lastname: Kvarnström
authors.forename: Djordje
authors.initials: D
authors.lastname: Musil
authors.forename: Ingemar
authors.initials: I
authors.lastname: Nilsson
authors.forename: Bertil
authors.initials: B
authors.lastname: Samulesson
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D006801:Humans; D020128:Inhibitory Concentration 50; D008958:Models, Molecular; D009025:Morpholines / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013917:Thrombin / Q000037:antagonists & inhibitors* / Q000737:chemistry*
chemical_list: D009025:Morpholines; D013917:Thrombin