Article
- The EMBO Journal (1999) 18, 5187 - 5194
- doi:10.1093/emboj/18.19.5187
Structure and mechanism of soluble quinoprotein glucose dehydrogenase
Arthur Oubrie1, Henriëtte J. Rozeboom1, Kor H. Kalk1, Arjen J.J. Olsthoorn2, Johannis A. Duine2 and Bauke W. Dijkstra1
- Laboratory of Biophysical Chemistry and BIOSON Research Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Department of Microbiology and Enzymology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
Correspondence to:
Bauke W. Dijkstra, E-mail: bauke@chem.rug.nl
Received 16 June 1999; Accepted 3 August 1999; Revised 3 August 1999
Abstract
Soluble glucose dehydrogenase (s-GDH; EC 1.1.99.17) is a classical quinoprotein which requires the cofactor pyrroloquinoline quinone (PQQ) to oxidize glucose to gluconolactone. The reaction mechanism of PQQ-dependent enzymes has remained controversial due to the absence of comprehensive structural data. We have determined the X-ray structure of s-GDH with the cofactor at 2.2 Å resolution, and of a complex with reduced PQQ and glucose at 1.9 Å resolution. These structures reveal the active site of s-GDH, and show for the first time how a functionally bound substrate interacts with the cofactor in a PQQ-dependent enzyme. Twenty years after the discovery of PQQ, our results finally provide conclusive evidence for a reaction mechanism comprising general base-catalyzed hydride transfer, rather than the generally accepted covalent addition-elimination mechanism. Thus, PQQ-dependent enzymes use a mechanism similar to that of nicotinamide- and flavin-dependent oxidoreductases.
Keywords:
- glucose dehydrogenase,
- hydride transfer,
- PQQ,
- reaction mechanism,
- X-ray structure
