Linked Life Data

19011912

Source:http://linkedlifedata.com/resource/pubmed/id/19011912

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2009-1-27
pubmed:abstractText
Hydrogenases are enzymes which catalyze the reversible cleavage of molecular hydrogen into protons and electrons. In [FeFe] hydrogenases the active center is a 6Fe6S cluster, referred to as the "H-cluster." It consists of the redox-active binuclear subcluster ([2Fe](H)) coordinated by CN(-) and CO ligands and the cubane-like [4Fe-4S](H) subcluster which is connected to the protein via Cys ligands. One of these Cys ligands bridges to the [2Fe](H) subcluster. The CO-inhibited form of [FeFe] hydrogenase isolated from Desulfovibrio desulfuricans was studied using advanced EPR methods. In the H(ox)-CO state the open coordination site at the [2Fe](H) subcluster is blocked by extrinsic CO, giving rise to an EPR-active S = 1/2 species. The CO inhibited state was prepared with (13)CO and illuminated under white light at 273 K. In this case scrambling of the CO ligands occurs. Three (13)C hyperfine couplings of 17.1, 7.4, and 3.8 MHz (isotropic part) were observed and assigned to (13)CO at the extrinsic, the bridging, and the terminal CO-ligand positions of the distal iron, respectively. No (13)CO exchange of the CO ligand to the proximal iron was observed. The hyperfine interactions detected indicate a rather large distribution of the spin density over the terminal and bridging CO ligands attached to the distal iron. Furthermore, (14)N nuclear spin interactions were measured. On the basis of the observed (14)N hyperfine couplings, which result from the CN(-) ligands of the [2Fe](H) subcluster, it has been concluded that there is very little unpaired spin density on the cyanides of the binuclear subcluster.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1432-1327
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
14
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
301-13
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Spin distribution of the H-cluster in the H(ox)-CO state of the [FeFe] hydrogenase from Desulfovibrio desulfuricans: HYSCORE and ENDOR study of (14)N and (13)C nuclear interactions.
pubmed:affiliation
Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, 45470, Mülheim a.d. Ruhr, Germany. silakov@mpi-muelheim.mpg.de
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't