Structure–function relationships of anaerobic gas-processing metalloenzymes

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Reactions involving H2, N2, CO, CO2 and CH4 are likely to have been central to the origin of life. This is indicated by the active-site structures of the enzymes involved, which are often reminiscent of minerals. Through the combined efforts of protein crystallography, various types of spectroscopy, theoretical calculations and model chemistry, it has been possible to put forward plausible mechanisms for gas-based metabolism by extant microorganisms. Although the reactions are based on metal centres, the protein matrix regulates reactivity and substrate and product trafficking through internal pathways, specific ligation and dielectricity.

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Figure 1: Active sites of gas-processing metalloenzymes.
Figure 2: Enzymatic catalysis.
Figure 3: Enzyme folds and substrate tunnels.
Figure 4: Active-site biosyntheses.
Figure 5: Model compounds.

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We thank D. M. Lawson and S. M. Mayer for providing data concerning the xenon sites in nitrogenase. We also thank the Commissariat à l'Energie Atomique and the Centre National de la Recherche Scientifique for institutional support, and the Agence Nationale de la Recherche and the BIOTEC programme of the European Union for funding.

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Fontecilla-Camps, J., Amara, P., Cavazza, C. et al. Structure–function relationships of anaerobic gas-processing metalloenzymes. Nature 460, 814–822 (2009) doi:10.1038/nature08299

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