Objective
The interpretation of the structure of hydrogenases, responsible for hydrogen metabolism in micro-organisms, should provide a basis for the optimized bioproduction of hydrogen and the design of improved, CO-resistant, fuel cells. These two aspects are central to the development of clean energy sources and as substituents of rapidly depleting fossil fuel sources. A recent report (The Economist 'Living with the car', June 22nd, 1996, pp. 3-18) clearly shows that the only alternative to internal-combustion motors that makes sense is the hybrid engine. In such engines methanol is used to produce H2 which, in turn, is oxidized to generate electricity in a continuous way. Three problems arise, however: 1) the high cost of the hydrogen-splitting catalyst (normally platinum) makes such engines very expensive, 2) the fuel cells can be poisoined by carbon oxides, by-products of the H2 generation process and 3) hydrogen is much more expensive than traditional fossil fuels. We intent to apply the knowledge gained by studying H2 biocatalysis to help solving these problems.
NiFe hydrogenases are bacterial enzymes that catalyse the reaction H<-> 2H+ + 2e . All the groups participating to this proposal have significantly contributed to the elucidation of the active site structure and function of these proteins through 1) crystallographic studies on the enzyme from the sulfate-reducing bacterium Desulfovibrio gigas (that have shown that the site is an heterobinuclear containing nickel and iron, with three diatomic ligands bound to the latter); 2) Fourier Transform Infrared spectroscopic analyses of Chromatium vinosum and D. gigas hydrogenases (that have indicated that the crystallographically detected Fe ligands are COCN-2 ); 3) redox titrations monitored by Electron Paramagnetic Resonance and IR that have identified several electronic states of the active site of hydrogenases and, 4) site-directed mutagenesis of several residues at or near the active site that has shown (in the homologous tetrameric hydrogenase from the aerobic, CO and O2 resistant bacterium Alcaligenes eutrophus ) which amino acids are essential for the integrity of the active site.
The picture emerging from these studies indicates that H2 biocatalysis is a complicated, fine-tuned process relying on an unusually complex active site (see cover). We propose to further our understanding of the catalytic mechanism of NiFe hydrogenases and their response to CO poisoning through a multidisciplinary approach including: 1) production and purification of native and mutated oxygen-sensitive and oxygen and CO-insensitive hydrogenases; 2) characterization of the sitedirected mutants by FTIR (both spectroscopy and spectroelectrochemistry), EPR, deuterium/hydrogen exchange and para/ortho H2 conversion; 3) high resolution crystallographic analyses of the reduced native, complexed enzyme and mutants of recombinant hydrogenases and, 4) interfacing of the various hydrogenases with solid electrodes to investigate electron transfer in the presence of CO and O2 Biomimetic models based on the knowledge acquired during the contract will be synthetized andtested electrochemically. It is expected that the information gathered within the network will benefit the industrial partner ENIRICERCHE in its efforts to improve hydrogen bioproduction Furthermore, our contacts with FUSINCO, a Spanish company with broad experience in fuel cell technology, will be intensify as technologically-relevant data are generated.
Fields of science (EuroSciVoc)
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
- natural scienceschemical sciencesinorganic chemistrytransition metals
- natural scienceschemical sciencescatalysisbiocatalysis
- natural scienceschemical sciencesorganic chemistryamines
- engineering and technologyenvironmental engineeringenergy and fuelsfuel cells
- natural sciencesbiological sciencesbiochemistrybiomoleculesproteinsenzymes
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Call for proposal
Data not availableFunding Scheme
CSC - Cost-sharing contractsCoordinator
38027 Grenoble
France