Project Details
Projekt
Multifrequency (9, 34 and 94 GHz) EPR investigations of paramagnetic intermediates in heterodisulfide reductase and related enzymes
Applicant
Professorin Dr. Marina Bennati
Subject Area
Structural Biology
Term
from 2009 to 2014
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 129926648
In this project we will employ state-of-the-art methods of electron paramagnetic resonance spectroscopy (EPR) at 9-, 34-, and 94 GHz frequencies to investigate the reaction mechanism of heterodisulfide reductase, a key enzyme in the energy metabolism of methane-producing archaea. The enzyme catalyses the reversible reduction of the heterodisulfide (CoM-S-S-CoB) to the thiol coenzymes, coenzyme M (CoM-SH) and coenzyme B (CoB-SH) in the final step of methanogenesis and employs an unusual 4Fe4S cluster to carry out substrate chemistry. Multifrequency ENDOR spectroscopy combined with selective isotopic labeling will permit determination of a detailed structure of the essential 4Fe4S-cluster and its interaction with the substrate. Freeze-quench EPR experiments on the millisecond time scale will be employed to identify further intermediates. In a major collaborative effort with other members of this consortium, including external collaborations, on Mössbauer spectroscopy, X-ray crystallography and quantum chemical calculations, the work will potentially emerge into a consistent mechanistic picture for this enzyme at the molecular level. The work will provide a basis to further investigate the hypothetical role of this enzyme in the energy conservation mechanism of other non-methanogenic organisms.
DFG Programme
Priority Programmes
