Download MendeleyAccumulating the hydride state in the catalytic cycle of [FeFe]-hydrogenases.
Winkler, M., Senger, M., Duan, J., Esselborn, J., Wittkamp, F., Hofmann, E., Apfel, U.P., Stripp, S.T., Happe, T.(2017) Nat Commun 8: 16115-16115
- PubMed: 28722011
- DOI: https://doi.org/10.1038/ncomms16115
- Primary Citation of Related Structures:
5LA3 - PubMed Abstract:
H 2 turnover at the [FeFe]-hydrogenase cofactor (H-cluster) is assumed to follow a reversible heterolytic mechanism, first yielding a proton and a hydrido-species which again is double-oxidized to release another proton. Three of the four presumed catalytic intermediates (H ox , H red /H red and H sred ) were characterized, using various spectroscopic techniques. However, in catalytically active enzyme, the state containing the hydrido-species, which is eponymous for the proposed heterolytic mechanism, has yet only been speculated about. We use different strategies to trap and spectroscopically characterize this transient hydride state (H hyd ) for three wild-type [FeFe]-hydrogenases. Applying a novel set-up for real-time attenuated total-reflection Fourier-transform infrared spectroscopy, we monitor compositional changes in the state-specific infrared signatures of [FeFe]-hydrogenases, varying buffer pH and gas composition. We selectively enrich the equilibrium concentration of H hyd , applying Le Chatelier's principle by simultaneously increasing substrate and product concentrations (H 2 /H + ). Site-directed manipulation, targeting either the proton-transfer pathway or the adt ligand, significantly enhances H hyd accumulation independent of pH.
Organizational Affiliation:
AG Photobiotechnologie, Lehrstuhl für Biochemie der Pflanzen, Fakultät für Biologie und Biotechnologie, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany.
