Linked Life Data

12022842

Source:http://linkedlifedata.com/resource/pubmed/id/12022842

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
2002-5-22
pubmed:abstractText
The (13)C pulsed ENDOR and NMR study of [meso-(13)C-TPPFe(OCH(3))(OO(t)Bu)](-) performed in this work shows that although the unpaired electron in low-spin ferrihemes containing a ROO(-) ligand resides in a d(pi) orbital at 8 K, the d(xy) electron configuration is favored at physiological temperatures. The variable temperature NMR spectra indicate a dynamic situation in which a heme with a d(pi) electron configuration and planar porphyrinate ring is in equilibrium with a d(xy) electron configuration that has a ruffled porphyrin ring. Because of the similarity in the EPR spectra of the hydroperoxide complexes of heme oxygenase, cytochrome P450, and the model heme complex reported herein, it is possible that these two electron configurations and ring conformations may also exist in equilibrium in the enzymatic systems. The ruffled porphyrinate ring would aid the attack of the terminal oxygen of the hydroperoxide intermediate of heme oxygenase (HO) on the meso-carbon, and the large spin density at the meso-carbons of a d(xy) electron configuration heme suggests the possibility of a radical mechanism for HO. The dynamic equilibrium between the ruffled (d(xy)) and planar (d(pi)) conformers observed in the model complexes also suggests that a flexible heme binding cavity may be an important structural motif for heme oxygenase activity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0002-7863
pubmed:author
pubmed:issnType
Print
pubmed:day
29
pubmed:volume
124
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6077-89
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Models of the low-spin iron(III) hydroperoxide intermediate of heme oxygenase: magnetic resonance evidence for thermodynamic stabilization of the d(xy) electronic state at ambient temperatures.
pubmed:affiliation
Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078-3071, USA. Rivera@okstate.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't