Site-selective protonation of the one-electron reduced cofactor in [FeFe]-hydrogenase

[FeFe] Hydrogenase: Protonation of {2Fe3S} Systems and Formation of Super-reduced Hydride States**

The synthesis and crystallographic characterization of a complex possessing a well-defined {2Fe3S(μ-H)} core gives access to a paramagnetic bridging hydride with retention of the core geometry. Chemistry of this 35-electron species within the confines of a thin-layer FTIR spectro-electrochemistry cell provides evidence for a unprecedented super-reduced Fe(I)(μ-H)Fe(I) intermediate.

Directing protonation in [FeFe] hydrogenase active site models by modifications in their second coordination sphere.

Subtle changes in the second coordination sphere of [Cl(2)bdtFe(2)(CO)(4)(Ph(2)P-CH(2)-X-CH(2)-PPh(2))] (bdt = benzene-1,2-dithiolate, X = NCH(3), NCH(2)CF(3), CH(2)) that do not influence the electronic character of the Fe(2) center can however direct protonation to three different sites: the N in the bis-phosphane, the Fe-Fe bond or the bdt-S.

Protonation of [FeFe]-hydrogenase sub-site analogues: revealing mechanism using FTIR stopped-flow techniques.

The formation of transient metal hydride(s) at the metallo-sulfur active sites of [FeFe]-hydrogenase is implicated in both hydrogen evolution and uptake reactions. Stopped-flow spectroscopic techniques can provide insight into the reactivity patterns of model {2Fe2S} sub-sites towards protons, and this information contributes to understanding the nature of the biological systems. In this study ...

Synthetic [FeFe] Hydrogenase Active Site Model Complexes

The [FeFe]-hydrogenase maturase HydF from Clostridium acetobutylicum contains a CO and CN- ligated iron cofactor.

Biosynthesis of the [FeFe] hydrogenases active site (H-cluster) requires three maturation factors whose respective roles are not understood yet. The clostridial maturation enzymes (CaHydE, CaHydF and CaHydG) were homologously overexpressed in their native host Clostridium acetobutylicum. CaHydF was able to activate Chlamydomonas reinhardtii [FeFe] hydrogenase apoprotein (CrHydA1(apo)) to almost...