Linked Life Data

19639134

Source:http://linkedlifedata.com/resource/pubmed/id/19639134

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
31
pubmed:dateCreated
2009-7-29
pubmed:abstractText
Hydrogenases are enzymes catalyzing the reversible heterolytic splitting of molecular hydrogen. Despite extensive investigations of this class of enzymes its catalytic mechanism is not yet well understood. In this paper spectroscopic investigations of the active site of [FeFe] hydrogenase are presented. The so-called H-cluster consists of a bi-nuclear catalytically active subcluster connected to a [4Fe4S] ferredoxin-like unit via a Cys-thiol bridge. An important feature of the H-cluster is that both irons in the bi-nuclear subcluster are coordinated by CN and CO ligands. The bi-nuclear site also carries a dithiol bridge, whose central atom has not yet been identified. Nitrogen and oxygen are the most probable candidates from a mechanistic point of view. Here we present a study of the (14)N nuclear quadrupole and hyperfine interactions of the active oxidized state of the H-cluster using advanced EPR methods. In total three (14)N nuclei with quadrupole couplings of 0.95 MHz, 0.35 MHz and 1.23 MHz were detected using hyperfine sublevel correlation spectroscopy (HYSCORE). The assignment of the signals is based on their (14)N quadrupole couplings in combination with DFT calculations. One signal is assigned to the CN ligand of the distal iron, one to a Lys side chain nitrogen and one to the putative nitrogen of the dithiol bridge. Hence, these results provide the first experimental evidence for a di-(thiomethyl)amine ligand (-S-CH(2)-NH-CH(2)-S-) in the bi-nuclear subcluster. This finding is important for understanding the mechanism of [FeFe] hydrogenases, since the nitrogen is likely to act as an internal base facilitating the heterolytic splitting/formation of H(2).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1463-9076
pubmed:author
pubmed:issnType
Print
pubmed:day
21
pubmed:volume
11
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6592-9
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
(14)N HYSCORE investigation of the H-cluster of [FeFe] hydrogenase: evidence for a nitrogen in the dithiol bridge.
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