title: Mechanistic characterization and crystal structure of a small molecule inactivator bound to plasminogen activator inhibitor-1.
abstract: Plasminogen activator inhibitor type-1 (PAI-1) is a member of the serine protease inhibitor (serpin) family. Excessive PAI-1 activity is associated with human disease, making it an attractive pharmaceutical target. However, like other serpins, PAI-1 has a labile structure, making it a difficult target for the development of small molecule inhibitors, and to date, there are no US Food and Drug Administration-approved small molecule inactivators of any serpins. Here we describe the mechanistic and structural characterization of a high affinity inactivator of PAI-1. This molecule binds to PAI-1 reversibly and acts through an allosteric mechanism that inhibits PAI-1 binding to proteases and to its cofactor vitronectin. The binding site is identified by X-ray crystallography and mutagenesis as a pocket at the interface of β-sheets B and C and α-helix H. A similar pocket is present on other serpins, suggesting that this site could be a common target in this structurally conserved protein family.
authors.affiliation: Departments of Pathology and Internal Medicine, Division of Cardiovascular Medicine, University of Michigan Medical School, Ann Arbor, MI 48109.
authors.forename: Shih-Hon
authors.initials: SH
authors.lastname: Li
authors.forename: Ashley A
authors.initials: AA
authors.lastname: Reinke
authors.forename: Karen L
authors.initials: KL
authors.lastname: Sanders
authors.forename: Cory D
authors.initials: CD
authors.lastname: Emal
authors.forename: James C
authors.initials: JC
authors.lastname: Whisstock
authors.forename: Jeanne A
authors.initials: JA
authors.lastname: Stuckey
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Lawrence
mesh_terms: D000494:Allosteric Regulation; D018360:Crystallography, X-Ray; D006801:Humans; D017395:Plasminogen Activator Inhibitor 1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship; D019096:Vitronectin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D017395:Plasminogen Activator Inhibitor 1; C051321:SERPINE1 protein, human; D019096:Vitronectin
keywords: cancer; fibrinolysis; fibrosis; thrombolysis