Title: Comparative analysis of the proteinase specificity in wild-type and stabilized plasminogen activator inhibitor-1: evidence for contribution of intramolecular flexibility
Authors: De Taeye, Bart
Gils, Ann
Vleugels, Nele
Rabijns, Anja
Declerck, Paul # ×
Issue Date: Aug-2004
Series Title: Biochemical and Biophysical Research Communications vol:321 issue:3 pages:746-51
Abstract: PAI-1, the physiological inhibitor of tissue-type and urokinase-type plasminogen activator, is a unique member of the serpins as it exists in three distinct conformations: an active inhibitory conformation, a non-inhibitory substrate conformation, and a non-reactive latent conformation. Proline substitution of single residues in the P16-P20 region (situated at the proximal hinge of the reactive site loop) of wild-type PAI-1 (wtPAI-1) and a stabilized PAI-1-variant (PAI-1-stab; N150H, K154T, Q301P, Q319L, and M354I, t(1/2)=150), respectively, resulted in two series of PAI-1-variants with different properties. In wtPAI-1 only substitution at P18 resulted in a pronounced u-PA specificity and substrate behaviour towards t-PA. In contrast, in PAI-1-stab substitution at either P18, P19 or P20 resulted in a u-PA specificity and a significantly increased substrate behaviour towards t-PA and u-PA. Importantly, analysis of the kinetics of inhibition did not reveal any differences in the second-order rate constants of inhibition (k approximately 10(7)M(-1)s(-1)). The pronounced differences observed for identical mutations in wtPAI-1 vs PAI-1-stab demonstrate that not merely the sequence of the reactive loop but also intramolecular interactions between the hF/s3A-loop and the main part of the molecule govern the functional and conformational behaviour of PAI-1.
ISSN: 0006-291X
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Laboratory for Pharmaceutical Biology (-)
× corresponding author
# (joint) last author

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