Angular dependence of electron paramagnetic resonances of an azide-NO complex of cytochrome c oxidase: orientation of the haem-copper axis in cytochrome aa3 from ox heart.
Biochim Biophys Acta
; 1364(1): 55-62, 1998 Apr 14.
Article
em En
| MEDLINE
| ID: mdl-9554953
ABSTRACT
The orientation dependence of the EPR signals arising from the azide-nitric oxide complex of cytochrome oxidase was investigated using oriented multilayers of mitochondrial membranes from ox heart. Variations in line shape of the DeltaMS=1 signal of the triplet state were apparent, whilst the DeltaMS=2 transitions between g=4.7 and 3.9 varied in intensity as the angle of the applied magnetic field was varied. These half-field signals were maximal with the field parallel to the membrane plane. A model of the bi-liganded azide-nitric oxide complex has been constructed, in which the nitric oxide is bound to the high-spin haem in a bent configuration, with the Fe-N=O plane at 60-90 degrees to the membrane plane and the azide bound to the copper, distal from the haem. In addition, angular variations of the signals at g'=11 and g' around 3.5, derived from an integer-spin complex, were also observed.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Complexo IV da Cadeia de Transporte de Elétrons
/
Mitocôndrias Cardíacas
Limite:
Animals
Idioma:
En
Ano de publicação:
1998
Tipo de documento:
Article