Low temperature magnetic circular dichroism spectra and magnetization properties of extracted heme a3+ bis-imidazole. A model of cytochrome a in bovine cytochrome c oxidase.
J Inorg Biochem
; 21(1): 1-8, 1984 May.
Article
em En
| MEDLINE
| ID: mdl-6327904
ABSTRACT
Heme a3+ isolated from bovine cardiac muscle cytochrome oxidase has been converted to the bis-imidazole species and studied by magnetic circular dichroism (MCD) spectroscopy. Spectra have been recorded down to 1.5 degrees K, enabling the MCD magnetization curves to be measured at a number of wavelengths in the visible and near infrared regions. The experimentally determined curves show excellent correlation to a curve using the g-values determined by electron paramagnetic resonance spectroscopy to be gz = 2.96, gy = 2.29, and gx = 1.73. The data show that the bis-imidazole derivative of extracted heme a3+ is an excellent model of cytochrome a in the enzyme, confirming the presence of two histidine residues in the protein as the fifth and sixth ligands. The spectral features of heme a3+ bis-imidazole in the near infrared region are consistent with transitions of the porphyrin ( a1u , a2u ) to ferric (eg) charge transfer type.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Complexo IV da Cadeia de Transporte de Elétrons
/
Citocromos
/
Heme
/
Imidazóis
Limite:
Animals
Idioma:
En
Ano de publicação:
1984
Tipo de documento:
Article