Redox state-dependent changes in the crystal structure of [NiFeSe] hydrogenase from Desulfovibrio vulgaris Hildenborough

Thiosulfate Dehydrogenase (TsdA) from Allochromatium vinosum

“…The Cys 96 sulfinate state probably results from oxidative damage during the long crystallization process at room temperature, as also observed in other enzymes (51). In the tetrathionate-soaked crystal, the partially persulfurated cysteine is also oxidized to the sulfinate state (PDB entry 4WQ8), whereas in the dithionite-reduced crystal, Cys 96 is found in two different states, either as a sulfinate or as the unmodified cysteine, and a sulfide was modeled coordinating the heme, which is not bound to Cys 96 (Fig.…”

Oxygen-tolerant proton reduction catalysis: much O2 about nothing?

“…Recent evidence has suggested that conversion from Ni-A to Ni-B is also assisted by the oxygenation of one of the bridging S-atoms. 55,56 The chemical role of selenocysteine in protecting the hydrogenase from oxidative damage is currently under investigation, 57 58 The O 2 tolerance may be a result of the easier oxidation and reduction of Se compared to S. 59 Due to the extreme O 2 sensitivity of many hydrogenases, engineering the enzymes to reduce protons and O 2 simultaneously is a significant challenge, 60,61 and currently Peters and coworkers showed in 2012 that a [NiFe] hydrogenase from Thiocapsa roseopersicina covalently linked to a Ru dye was able to photocatalytically reduce protons under aerobic conditions in the presence of the soluble redox mediator methyl viologen (MV) and a sacrificial electron donor. 42 The [NiFeSe] hydrogenase is a subclass of the [NiFe] hydrogenase that is highly active for proton reduction in the presence of H 2 and illustrates a promising degree of tolerance to O 2 .…”

A Post-Genomic View of the Ecophysiology, Catabolism and Biotechnological Relevance of Sulphate-Reducing Prokaryotes

“…In D. vulgaris Hildenborough and other organisms, the Hys [NiFeSe] and Hyn-1 [NiFe] hydrogenases are bacterial lipoproteins bound to the membrane through a lipidic group present at the N-terminus of the large subunit(Valente et al, 2007). The[NiFeSe] hydrogenase has a high activity for H 2 production(Valente et al, 2005) and does not form the typical Ni-A inactive state of [NiFe] hydrogenases(Marques, Coelho, De Lacey, Pereira, & Matias, 2010;Marques, Coelho, Pereira, & Matias, 2013), making it an appealing target for bioelectrochemical applications. It can be immobilized on electrodes allowing for direct electron transfer (Gutiérrez…”