[FeFe]-hydrogenases are among the most efficient H2-producing catalysts known, and there is therefore great interest in elucidating the mechanism of these unique enzymes.  We are particularly interested in the intramolecular transport of substrates.  Many bacterial [FeFe]-hydrogenases appear to contain a bifurcated electron transport pathway, and experiments in our lab are designed to elucidate the role of these two different pathways.  In addition, proton transfer is an essential component of reversible hydrogen production, and we recently identified four amino acid residues in the [FeFe]-hydrogenase from Clostridium pasteurianum that form a proton pathway from the active site to the enzyme surface.  Amino acid substitution of any of these residues drastically reduces both H2 uptake and H2 production, indicating that the two reactions utilize the same pathway.  Importantly, all four of these residues are strictly conserved, suggesting that the mechanism of proton transfer may be common to all [FeFe]-hydrogenases.

Proton and electron transfer in [FeFe]-hydrogenases

243rd National Meeting (2012)

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