Cytochrome d axial ligand of the bd-type terminal quinol oxidase from Escherichia coli.
FEBS Lett
; 335(1): 13-7, 1993 Nov 29.
Article
em En
| MEDLINE
| ID: mdl-8243657
ABSTRACT
Using various spectroscopic techniques, we studied the structure of the dioxygen reduction site of the bd-type terminal quinol oxidase in the aerobic respiratory chain of Escherichia coli. Resonance Raman and FT-IR spectroscopies identified the v(Fe(2+)-CO) and v(C-O) stretching frequencies at 471 and 1980.7 cm-1, respectively, at the cytochrome d center of the dithionite-reduced CO-bound enzyme. The CO ligation in the cytochrome bd complex is considerably different from those of the heme-copper terminal oxidases. Anaerobic addition of NO to the air-oxidized enzyme caused an exchange of cytochrome d-bound dioxygen with NO leading to an appearance of cytochrome d-NO EPR signal. But there is no superhyperfine structure originating from the cytochrome d proximal 14N ligand in the central resonance of the NO EPR signal. These results suggest that cytochrome d axial ligand of the cytochrome bd complex is likely a histidine residue in an anomalous condition or other than a histidine residue and, therefore, the molecular structure around the dioxygen-binding site is different from that of the heme-copper terminal oxidases.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oxirredutases
/
Grupo dos Citocromos d
/
Proteínas de Escherichia coli
/
Complexo de Proteínas da Cadeia de Transporte de Elétrons
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Escherichia coli
Idioma:
En
Ano de publicação:
1993
Tipo de documento:
Article