Covalently bound substrate at the regulatory site triggers allosteric enzyme activation

  • The mechanism by which the enzyme pyruvate decarboxylase from yeast is activated allosterically has been elucidated. A total of seven three-dimensional structures of the enzyme, of enzyme variants or of enzyme complexes from two yeast species (three of them reported here for the first time) provide detailed atomic resolution snapshots along the activation coordinate. The prime event is the covalent binding of the substrate pyruvate to the side chain of cysteine 221, thus forming a thiohemiketal. This reaction causes the shift of a neighbouring amino acid, which eventually leads to the rigidification of two otherwise flexible loops, where one of the loops provides two histidine residues necessary to complete the enzymatically competent active site architecture. The structural data are complemented and supported by kinetic investigations and binding studies and provide a consistent picture of the structural changes, which occur upon enzyme activation.

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Author:Steffen Kutter, Manfred S. Weiss, Georg Wille, Ralph Golbik, Michael Spinka, Stephan König
Document Type:Preprint
Date of Publication (online):2009/10/07
Year of first Publication:2008
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2009/10/07
This document is licensed to the public under the Creative Commons Attribution 3.0 License
Institutes:Physik / Physik
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Sammlungen:Sammlung Biologie / Sondersammelgebiets-Volltexte
Licence (German):License LogoCreative Commons - Namensnennung 3.0