Linked Life Data

16854984

Source:http://linkedlifedata.com/resource/pubmed/id/16854984

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
37
pubmed:dateCreated
2006-9-11
pubmed:abstractText
The interaction of the reduced[2Fe-2S] cluster of isolated Rieske fragment from the bc1 complex of Rhodobacter sphaeroides with nitrogens (14N and 15N) from the local protein environment has been studied by X- and S-band pulsed EPR spectroscopy. The two-dimensional electron spin echo envelope modulation spectra of uniformly 15N-labeled protein show two well resolved cross-peaks with weak couplings of approximately 0.3-0.4 and 1.1 MHz in addition to couplings in the range of 6-8 MHz from two coordinating Ndelta of histidine ligands. The quadrupole coupling constants for weakly coupled nitrogens determined from S-band electron spin echo envelope modulation spectra identify them as Nepsilon of histidine ligands and peptide nitrogen (Np), respectively. Analysis of the line intensities in orientation-selected S-band spectra indicated that Np is the backbone N-atom of Leu-132 residue. The hyperfine couplings from Nepsilon and Np demonstrate the predominantly isotropic character resulting from the transfer of unpaired spin density onto the 2s orbitals of the nitrogens. Spectra also show that other peptide nitrogens in the protein environment must carry a 5-10 times smaller amount of spin density than the Np of Leu-132 residue. The appearance of the excess unpaired spin density on the Np of Leu-132 residue indicates its involvement in hydrogen bond formation with the bridging sulfur of the Rieske cluster. The configuration of the hydrogen bond therefore provides a preferred path for spin density transfer. Observation of similar splittings in the 15N spectra of other Rieske-type proteins and [2Fe-2S] ferredoxins suggests that a hydrogen bond between the bridging sulfur and peptide nitrogen is a common structural feature of [2Fe-2S] clusters.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
281
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
27416-25
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Identification of hydrogen bonds to the Rieske cluster through the weakly coupled nitrogens detected by electron spin echo envelope modulation spectroscopy.
pubmed:affiliation
Department of Veterinary Clinical Medicine, University of Illinois, Urbana, Illinois 61801, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, N.I.H., Extramural