Research interests AG Molecular Enzymology
Research interests
Research in our laboratories focuses on the mechanistic elucidation of thiamin diphosphate (the vitamin B1 coenzyme) and flavin (the vitamin B2 coenzyme)-dependent enzymes.
We aim to understand how these enzymes accomplish the effective transition state stabilisation in the course of catalysis.
Studies on thiamin-dependent enzymes
We attempt to illuminate the reaction mechanism of various thiamin enzymes at a molecular level by the combined use of kinetic, structural and theoretical studies. Particular emphasis is laid on the detection of on-pathway intermediates using NMR spectroscopy and X-ray crystallography (in collaboration with Dr. G. Wille and Prof. M. Stubbs).
Current projects address the mechanistic analysis of pyruvate oxidase, pyruvate decarboxylase, pyruvate dehydrogenase, acetohydroxyacid synthase, glyoxylate carboligase and transketolase.
Studies on flavoenzymes
We are interested in the kinetic and thermodynamic analysis of biological electron transfer reactions, in particular in these involving the thiamin and flavin cofactors. In another project, factors that govern the modulation of the redox potential of enzyme-bound flavins are being studied.
Major biophysical tools used cover
detailed single step kinetics (stopped-flow, rapid quench-flow / NMR spectroscopy, rapid freeze-quench / EPR spectroscopy, NMR spectroscopy),
thermodynamic studies (redox potentiometry, isothermal titration calorimetry),
and structural studies (X-ray crystallography, fluorescence resonance energy transfer (FRET)).
Collaborations
Prof. G. Hübner and Dr. R. Golbik, University of Halle
Prof. D.M. Chipman, University of the Negev, Beer-Sheva
Prof. S. Ghisla, Konstanz University
Prof. F. Jordan, Rutgers University, Newark, NJ
Prof. R.G. Duggleby, University of Queensland, Brisbane
Dr. J. Seravalli and Prof. S.W. Ragsdale, University of Nebraska, Lincoln
Prof. G. Reed, University of Wisconsin
Prof. M. Patel, University of New York, Buffalo
Prof. D. Kern, Brandeis University
Prof. G. Schneider, Karolinska Institutet, Stockholm
Dr. G. Wille, University Frankfurt/Main
Prof. M. Stubbs, University of Halle
Prof. A. Blume, University of Halle
Dr. M. Pohl, Julich Research Centre
Prof. R. Kluger, University of Toronto
Prof. R. Schowen, Kansas University
Dr. R. Friedemann, University of Halle
Prof. W. Buckel and Dr. A. Pierik, University of Marburg
Prof. B. Eikmanns, University of Ulm
Prof. P. Kroneck, Konstanz University
Prof. J. Balbach, University of Halle