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The iron‐sulfur centers of the soluble [NiFeSe] hydrogenase, from Desulfovibrio baculatus (DSM 1743)

1990; Wiley; Volume: 189; Issue: 2 Linguagem: Inglês

10.1111/j.1432-1033.1990.tb15499.x

1432-1033

Miguel Teixeira, Isabel Moura, Guy Fauque, Daniel V. DerVartanian, Jean LeGall, H.D. Peck, José J. G. Moura, Boi Hanh Huynh,

Hydrogen Storage and Materials

The soluble (cytoplasmic plus periplasmic) Ni/Fe‐S/Se‐containing hydrogenase from Desulfovibrio baculatus (DSM 1743) was purified from cells grown in an 57 Fe‐enriched medium, and its iron‐sulfur centers were extensively characterized by Mössbauer and EPR spectroscopies. The data analysis excludes the presence of a [3Fe‐4S] center, either in the native (as isolated) or in the hydrogen‐reduced states. In the native state, the non‐heme iron atoms are arranged as two diamagnetic [4Fe‐4S] 2+ centers. Upon reduction, these two centers exhibit distinct and unusual Mössbauer spectroscopic parameters. The centers were found to have similar mid‐point potentials (∼– 315 mV) as determined by oxidation‐reduction titrations followed by EPR.