Linked Life Data

10393326

Source:http://linkedlifedata.com/resource/pubmed/id/10393326

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1999-10-28
pubmed:abstractText
Cytochrome bd-type ubiquinol oxidase in the aerobic respiratory chain of Escherichia coli contains two hemes b (b558 and b595) and one heme d as redox metal centers. To clarify the structure of the reaction center, we analyzed the fully oxidized enzyme by visible and EPR spectroscopies using fluoride ion as a monitoring probe. The visible spectral changes upon fluoride-binding were typical of ferric iron-chlorine species, indicating heme d as a primary binding site. The negative peak at 645 nm in the difference spectrum indicates that heme b595 also provides the low-affinity fluoride-binding site. Fluoride-binding caused a complete disappearance from the EPR spectra of the low-spin signals ascribable to heme d and spectral changes in both rhombic and axial high-spin signals. After fluoride-binding, each component of the rhombic high-spin signal showed superhyperfine splitting arising from the interaction of the unpaired spin of the heme d iron with the nuclear magnetic moment of 19F. The axial high-spin species was converted to a new rhombic high-spin species assignable to heme b595-fluoride. The g = 2 component of this new species also gave 19F-superhyperfine splitting. These results indicate that both heme d and heme b595 can coordinate with a fluoride ion with different affinities in the fully oxidized state.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0021-924X
pubmed:author
pubmed:issnType
Print
pubmed:volume
126
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
98-103
pubmed:dateRevised
2007-12-19
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Fluoride-binding to the Escherichia coli bd-type ubiquinol oxidase studied by visible absorption and EPR spectroscopies.
pubmed:affiliation
Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigoori-cho, Akou-gun, Hyogo, 678-1297, Japan. tsubaki@sci.himeji-tech.ac.jp
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't