Work

Distortion of the Catalytic Domain of Tissue-type Plasminogen Activator by Plasminogen Activator Inhibitor-1 Coincides with the Formation of Stable Serpin-Proteinase Complexes

Year: 2003

Type: article

Abstract: Plasminogen activator inhibitor-1 (PAI-1) is a typical member of the serpin family that kinetically traps its target proteinase as a covalent complex by distortion of the proteinase domain. Incorporation of the fluorescently silent 4-fluorotryptophan analog into PAI-1 permitted us to observe changes in the intrinsic tryptophan fluorescence of two-chain tissue-type plasminogen activator (tPA) and the proteinase domain of tPA during the inhibition reaction. We demonstrated three distinct conformational changes of the proteinase that occur during complex formation and distortion. A conformational change occurred during the initial formation of the non-covalent Michaelis complex followed by a large conformational change associated with the distortion of the proteinase catalytic domain that occurs concurrently with the formation of stable proteinase-inhibitor complexes. Following distortion, a very slow structural change occurs that may be involved in the stabilization or regulation of the trapped complex. Furthermore, by comparing the inhibition rates of two-chain tPA and the proteinase domain of tPA by PAI-1, we demonstrate that the accessory domains of tPA play a prominent role in the initial formation of the non-covalent Michaelis complex.

Source: Journal of Biological Chemistry

DOI: 10.1074/jbc.m306184200

Authors: Michel J. Perron, Grant E. Blouse, Joseph D. Shore

Institutions: Henry Ford Health, Wayne State University

Language: English

Topic: Protease and Inhibitor Mechanisms

Subfield: Cancer Research

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: hybrid

Estimated APC paid: $3,430

Funders: National Institutes of Health, National Heart, Lung, and Blood Institute