Structural investigations by extended X-ray absorption fine structure spectroscopy of the iron center of mitochondrial aconitase in higher plant cells.
J Biol Chem
; 267(24): 16775-8, 1992 Aug 25.
Article
em En
| MEDLINE
| ID: mdl-1324911
ABSTRACT
We have obtained iron K-edge extended x-ray absorption fine structure spectra of the plant mitochondrial aconitase in its active state, in the presence (aconitase (+)) and absence (aconitase (-)) of the substrate citrate. Analysis of the data indicates that oxygens are present in the first coordination shell, at an average Fe-O distance of 1.96/1.98 A (aconitase (+)/aconitase(-)). Part of these oxygens is provided by the citrate, which binds at 1.99 A from the iron in aconitase (+). The second shell (sulfur) contribution is split and is consistent with Fe-S distances of 2.30/2.29 and 2.56/2.59 A, and the third shell (iron) is consistent with an Fe-Fe distance of 2.83/2.84 A. Both Fe-S and Fe-Fe distances are longer than similar distances found in most Fe-S centers. A strong scattering at approximately 5 A has been identified as originating from an iron atom which is near to, but not part of, the Fe-S cluster. These data indicate that active plant mitochondrial aconitase contains a novel type of iron center.
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Base de dados:
MEDLINE
Assunto principal:
Aconitato Hidratase
/
Solanum tuberosum
/
Mitocôndrias
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
1992
Tipo de documento:
Article
País de afiliação:
França