Characterization of a unique [FeS] cluster in the electron transfer chain of the oxygen tolerant [NiFe] hydrogenase from Aquifex aeolicus.

ABSTRACT: Iron-sulfur clusters are versatile electron transfer cofactors, ubiquitous in metalloenzymes such as hydrogenases. In the oxygen-tolerant Hydrogenase I from Aquifex aeolicus such electron "wires" form a relay to a diheme cytb, an integral part of a respiration pathway for the reduction of O(2) to water. Amino acid sequence comparison with oxygen-sensitive hydrogenases showed conserved binding motifs for three iron-sulfur clusters, the nature and properties of which were unknown so far. Electron paramagnetic resonance spectra exhibited complex signals that disclose interesting features and spin-coupling patterns; by redox titrations three iron-sulfur clusters were identified in their usual redox states, a [3Fe4S] and two [4Fe4S], but also a unique high-potential (HP) state was found. On the

SUBMITTER: Pandelia ME 

PROVIDER: S-EPMC3076877 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature