The membrane-bound [NiFe] hydrogenase from the hyperthermophile Aquifex aeolicus is thermostable and oxygen tolerant (1). According to EPR experiments the O2-inhibited Ni-A state found in O2-sensitive hydrogenases is absent; the oxidized Ni-B state shows a complex spin-coupled signal (2). The key catalytic species Ni-C has the substrate (hydride) bound, albeit with differences likely important for catalysis. Spectroelectrochemical titrations show that the redox potentials of the active site and the iron-sulfur cofactors of the electron transfer chain are higher than in O2-sensitive hydrogenases (1,2). O2-tolerance in these enzymes is found to be multifactorial and essentially dependent on the presence of the proximal special [4Fe3S] cluster ligated by six cysteines (3) that can undergo two redox transitions (2).(1) M.E. Pandelia et al. J. Am. Chem. Soc. 2010 , 132, 6991(2) M.E. Pandelia et al. Proc. Natl. Acad. Sci. USA 2011 , 108, 6097(3) Y. Shomura et al. Nature 2011 , in press

Hydrogen conversion in nature in the presence of oxygen: The [NiFe] hydrogenase I from <i>Aquifex aeolicus</i>

243rd National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Hydrogen conversion in nature in the presence of oxygen: The [NiFe] hydrogenase I from Aquifex aeolicus