title: A selective, slow binding inhibitor of factor VIIa binds to a nonstandard active site conformation and attenuates thrombus formation in vivo.
abstract: The serine protease factor VIIa (FVIIa) in complex with its cellular cofactor tissue factor (TF) initiates the blood coagulation reactions. TF.FVIIa is also implicated in thrombosis-related disorders and constitutes an appealing therapeutic target for treatment of cardiovascular diseases. To this end, we generated the FVIIa active site inhibitor G17905, which displayed great potency toward TF.FVIIa (Ki = 0.35 +/- 0.11 nM). G17905 did not appreciably inhibit 12 of the 14 examined trypsin-like serine proteases, consistent with its TF.FVIIa-specific activity in clotting assays. The crystal structure of the FVIIa.G17905 complex provides insight into the molecular basis of the high selectivity. It shows that, compared with other serine proteases, FVIIa is uniquely equipped to accommodate conformational disturbances in the Gln217-Gly219 region caused by the ortho-hydroxy group of the inhibitor's aminobenzamidine moiety located in the S1 recognition pocket. Moreover, the structure revealed a novel, nonstandard conformation of FVIIa active site in the region of the oxyanion hole, a "flipped" Lys192-Gly193 peptide bond. Macromolecular substrate activation assays demonstrated that G17905 is a noncompetitive, slow-binding inhibitor. Nevertheless, G17905 effectively inhibited thrombus formation in a baboon arterio-venous shunt model, reducing platelet and fibrin deposition by approximately 70% at 0.4 mg/kg + 0.1 mg/kg/min infusion. Therefore, the in vitro potency of G17905, characterized by slow binding kinetics, correlated with efficacious antithrombotic activity in vivo.
authors.affiliation: Department of Medicinal Chemistry, Genentech, Inc., South San Francisco, California 94080, USA.
authors.forename: Alan G
authors.initials: AG
authors.lastname: Olivero
authors.forename: Charles
authors.initials: C
authors.lastname: Eigenbrot
authors.forename: Richard
authors.initials: R
authors.lastname: Goldsmith
authors.forename: Kirk
authors.initials: K
authors.lastname: Robarge
authors.forename: Dean R
authors.initials: DR
authors.lastname: Artis
authors.forename: John
authors.initials: J
authors.lastname: Flygare
authors.forename: Thomas
authors.initials: T
authors.lastname: Rawson
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Sutherlin
authors.forename: Saloumeh
authors.initials: S
authors.lastname: Kadkhodayan
authors.forename: Maureen
authors.initials: M
authors.lastname: Beresini
authors.forename: Linda O
authors.initials: LO
authors.lastname: Elliott
authors.forename: Geralyn G
authors.initials: GG
authors.lastname: DeGuzman
authors.forename: David W
authors.initials: DW
authors.lastname: Banner
authors.forename: Mark
authors.initials: M
authors.lastname: Ultsch
authors.forename: Ulla
authors.initials: U
authors.lastname: Marzec
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Hanson
authors.forename: Canio
authors.initials: C
authors.lastname: Refino
authors.forename: Stuart
authors.initials: S
authors.lastname: Bunting
authors.forename: Daniel
authors.initials: D
authors.lastname: Kirchhofer
mesh_terms: D001550:Benzamidines / Q000494:pharmacology*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D015942:Factor VIIa / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D006860:Hydrogen Bonding; D007700:Kinetics; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D013449:Sulfonamides / Q000494:pharmacology*; D013927:Thrombosis / Q000517:prevention & control
chemical_list: C499651:4-(2-(3-aminobenzenesulfonylamino)-1-(3,5-diethoxy-2-fluorophenyl)-2-oxoethylamino)-2-hydroxybenzamidine; D001550:Benzamidines; D013449:Sulfonamides; D015942:Factor VIIa