Rational design of complex formation between plasminogen activator inhibitor-1 and its target proteinases.
Considerable progress in understanding the mechanism of inhibition of proteinases by serpins has been obtained from different biochemical studies. These studies reveal that stable serpin/proteinase complex formation involves insertion of the reactive-site loop of the serpin and occurs at the acyl-enzyme stage. Even though no three-dimensional structure of a serpin/proteinase complex is resolved, structural information is available on some of the individual compounds. Molecular modeling techniques combined with recently acquired biochemical/biophysical data were used to provide insight into the stable complex formation between plasminogen activator inhibitor-1 (PAI-1) and the target proteinases: tissue-type plasminogen activator, urokinase-type plasminogen activator, and thrombin. This study reveals that PAI-1 initially interacts with its target proteinase when its reactive-site loop is solvent exposed and thereby accessible for the proteinase. Stable complex formation, however, involves the insertion of the reactive-site loop up to P7 and results in a tight binding geometry between PAI-1 and its target proteinase. The influence of different biologically relevant molecules on PAI-1/proteinase complex formation and the differences in inhibition rate constants observed for the different proteinases can be explained from these models.
Aertgeerts
K
K
Laboratory for Analytical Chemistry and Medicinal Physicochemistry, Faculty of Pharmaceutical Sciences, Belgium.
De Ranter
C J
CJ
Booth
N A
NA
Declerck
P J
PJ
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D010450:Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D017395:Plasminogen Activator Inhibitor 1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D015843:Serpins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014568:Urokinase-Type Plasminogen Activator / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D046911:Macromolecular Substances; D017395:Plasminogen Activator Inhibitor 1; D015843:Serpins; D010450:Endopeptidases; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator