Biomimetic approach to the oxygen evolving center: resonance Raman investigation of a manganese mu-oxo dimer in three oxidation states.

A biologically relevant dinuclear manganese mono-mu-oxo complex with a bound phenolate ligand in three oxidation states, (III,III), (III,IV) and (IV,IV), was studied using resonance Raman spectroscopy. Depending upon the excitation frequency, phenolate vibrations or mu-oxo vibrations were enhanced, which allowed us to assign the UV-visible absorption spectra. In the case of the mixed valence species (III,IV), the mu-oxo vibration at 854 cm-1 has been assigned by isotopic substitution (H2(18)O) to nu as(Mn-O-Mn).

Enzyme-mediated sulfide production for the reconstitution of [2Fe-2S] clusters into apo-biotin synthase of Escherichia coli. Sulfide transfer from cysteine to biotin.

We previously showed that biotin synthase in which the (Fe-S) cluster was labelled with 34S by reconstitution donates 34S to biotin [B. Tse Sum Bui, D. Florentin, F.

Resonance Raman study of multihemic c-type cytochromes from Desulfuromonas acetoxidans.

Two multihemic cytochromes c from the sulfur reducing bacteria Desulfuromonas acetoxidans have been studied by optical and resonance Raman spectroscopy: cytochrome c551.5, a trihemic cytochrome and cytochrome c Mr 50 000, a recently isolated high molecular mass cytochrome. The redox and Raman characteristics of cytochrome c551.

A Pentacoordinated Di-N-carboxamido-dithiolato-O-sulfinato-iron(III) Complex Related to the Metal Site of Nitrile Hydratase.

Postcoordination oxidation by dioxygen of one of the thiolate groups in a pentadentate N(2)S(3) ligand results in an iron(III) complex with two N-carboxamido, two thiolato, and one O-sulfinato ligands (see the CAMERON representation). This novel mixed coordination is similar to that determined for the inactive form of the nitrile hydratase from Rhodococcus sp. N-771, but differs by the O versus S binding of the sulfinato ligand.

Engineering, expression and biochemical characterization of the hemoglobin domain of a Erwinia chrysanthemi flavohemoprotein.

An artificial hemoglobin-like domain has been constructed by engineering the gene coding for the multi-domain flavohemoprotein from the bacterium Erwinia chrysanthemi. This domain was designed by molecular modelling, cloned and over-expressed in Escherichia coli. The holo-protein was obtained in large quantities after extraction from inclusion bodies and refolding in presence of alkaline hemin.