Linked Life Data

21444783

Source:http://linkedlifedata.com/resource/pubmed/id/21444783

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
15
pubmed:dateCreated
2011-4-13
pubmed:abstractText
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 basis of (57)Fe Mössbauer spectroscopy we attribute this HP form to a superoxidized state of the [4Fe4S] center proximal to the [NiFe] site. The unique environment of this cluster, characterized by a surplus cysteine coordination, is able to tune the redox potentials and make it compliant with the [4Fe4S](3+) state. It is actually the first example of a biological [4Fe4S] center that physiologically switches between 3+, 2+, and 1+ oxidation states within a very small potential range. We suggest that the (1 + /2+) redox couple serves the classical electron transfer reaction, whereas the superoxidation step is associated with a redox switch against oxidative stress.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1091-6490
pubmed:author
pubmed:issnType
Electronic
pubmed:day
12
pubmed:volume
108
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6097-102
pubmed:dateRevised
2011-10-12
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Characterization of a unique [FeS] cluster in the electron transfer chain of the oxygen tolerant [NiFe] hydrogenase from Aquifex aeolicus.
pubmed:affiliation
Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim ad Ruhr, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't