Active site structure of SoxB-type cytochrome bo3 oxidase from thermophilic Bacillus.
J Inorg Biochem
; 82(1-4): 65-72, 2000 Nov.
Article
en En
| MEDLINE
| ID: mdl-11132640
Two-subunit SoxB-type cytochrome c oxidase in Bacillus stearothermophilus was over-produced, purified, and examined for its active site structures by electron paramagnetic resonance (EPR) and resonance Raman (RR) spectroscopies. This is cytochrome bo3 oxidase containing heme B at the low-spin heme site and heme O at the high-spin heme site of the binuclear center. EPR spectra of the enzyme in the oxidized form indicated that structures of the high-spin heme O and the low-spin heme B were similar to those of SoxM-type oxidases based on the signals at g=6.1, and g=3.04. However, the EPR signals from the CuA center and the integer spin system at the binuclear center showed slight differences. RR spectra of the oxidized form showed that heme O was in a 6-coordinated high-spin (nu3 = 1472 cm(-1)), and heme B was in a 6-coordinated low-spin (nu3 = 1500 cm(-1)) state. The Fe2+-His stretching mode was observed at 211 cm(-1), indicating that the Fe2+-His bond strength is not so much different from those of SoxM-type oxidases. On the contrary, both the Fe2+-CO stretching and Fe2+-C-O bending modes differed distinctly from those of SoxM-type enzymes, suggesting some differences in the coordination geometry and the protein structure in the proximity of bound CO in cytochrome bo3 from those of SoxM-type enzymes.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Geobacillus stearothermophilus
/
Complejo IV de Transporte de Electrones
/
Citocromos
Idioma:
En
Revista:
J Inorg Biochem
Año:
2000
Tipo del documento:
Article
País de afiliación:
Japón
Pais de publicación:
Estados Unidos