tailieunhanh - Báo cáo khoa học: The crystal structure of pyruvate decarboxylase from Kluyveromyces lactis Implications for the substrate activation mechanism of this enzyme

The crystal structure of pyruvate decarboxylase fromKluyveromyces lactis has been determined to A˚ resolution. Like other yeast enzymes, Kluyveromyces lactispyruvate decarboxylase is subject to allosteric sub-strate activation. Binding of substrate at a regulatory site induces catalytic activity. | ỊFEBS Journal The crystal structure of pyruvate decarboxylase from Kluyveromyces lactis Implications for the substrate activation mechanism of this enzyme Steffen Kutter1 Georg Wille1 Sandy Relle1 Manfred S. Weiss2 Gerhard Hubner1 and Stephan Konig1 1 Institute for Biochemistry Department of Biochemistry Biotechnology Martin-Luther-University Halle-Wittenberg Halle Saale Germany 2 European Molecular Biology Laboratory Outstation Hamburg Germany Keywords allosteric enzyme activation conformation equilibrium disordered loop regions thiamine diphosphate Correspondence S. Konig Institute for Biochemistry Department of Biochemistry Biotechnology Martin-Luther-University Halle-Wittenberg Kurt-Mothes-Str. 3 06120 Halle Saale Germany Fax 49 345 5527014 Tel 49 345 5524829 E-mail koenig@ Present address Institute for Biophysics Department of Physics Johann-Wolfgang-Goethe-University Frankfurt Main Max-von-Laue-Str. 1 60438 Frankfurt Main Germany Received 19 June 2006 accepted 13 July 2006 doi The crystal structure of pyruvate decarboxylase from Kluyveromyces lactis has been determined to A resolution. Like other yeast enzymes Kluyveromyces lactis pyruvate decarboxylase is subject to allosteric substrate activation. Binding of substrate at a regulatory site induces catalytic activity. This process is accompanied by conformational changes and subunit rearrangements. In the nonactivated form of the corresponding enzyme from Saccharomyces cerevisiae all active sites are solvent accessible due to the high flexibility of loop regions 106-113 and 292-301. The binding of the activator pyruvamide arrests these loops. Consequently two of four active sites become closed. In Kluyveromyces lactis pyruvate decarboxylase this half-side closed tetramer is present even without any activator. However one of the loops residues 105-113 which are flexible in nonactivated Saccharomyces cerevisiae pyruvate decarboxylase remains .