Gallery

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See also the movies shown in these posts.

The structure of the H-cluster of FeFe hydrogenase

Cartoons illustrating the usages of H2ases. Note that every device should suffer from the sensitivity of the enzyme to O2, light, or very low or high potentials. (a) In a biofuel cell, electricity is produced by coupling high potential H2-oxidation by adsorbed H2ase to O2-reduction by adsorbed laccase (Vincent 2005, 2006). (b) Electricity generation coupled to low potential hydrogen production in a photoelectrochemical cell (Hambourger 2008). (c) Coupling of H2ase and another oxidoreductase on a graphite nanoparticle (Vincent 2007). (d) Hydrogen photoproduction by H2ase coupled to a Ru sensitizer on a TiO2 particle (Reisner 2009). (e) Hydrogenase covalently attached to Photosystem I for the photoproduction of H2 (Lubner 2010). (f) Biological hydrogen photoproduction by cultures of photosynthetic algae (Stripp 2009).

Overlay of the structures of C. acetobutylicum (red) and C. reinhardtii (blue) FeFe hydrogenases

Overlay of the structures of C. acetobutylicum (red), D. desulfuricans (green) and C. reinhardtii (blue) FeFe hydrogenases

Panel A: the FeFe active site H-cluster. Panel B: the backbones of the FeFe hydrogenases from C. acetobutylicum (green trace, pdb 3C8Y) and C. reinhardtii (blue trace, pdb 3LX4). Panels C and D: the active site and the backbone of the NiFe hydrogenase from D. fructosovorans, and aminoacids that shape the sub- strate gas channel (pdb 1YQ9). The chains of FeS clusters that are used for long- range electron transfer are visible in panels B and D. From ref The mechanism of inhibition by H2 of H2-evolution by hydrogenases

Une collection de voltammogrammes catalytiques aux formes complexes, obtenus avec des enzymes échangeant des électrons directement avec une électrode tournante. Les courants positifs (resp., négatifs) révèlent une réaction d’oxydation (resp., de réduction). Les flèches indiquent le sens du balayage du potentiel. Panel A: oxydation du succinate par la fumarate réductase de Escherichia coli; B: réduction du fumarate par la fumarate réductase de E. coli; C et D: oxydation du dihydrogène par un mutant de l’hydrogénases de Chlamydomonas reinhardtii et l’hydrogénase sauvage de Aquifex aeolicus; E et F: réduction du nitrate par la nitrate réductase de Rhodobacter sphaeroides.

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