31P nuclear magnetic resonance study of the flavoprotein component of the Escherichia coli sulfite reductase.
Eur J Biochem
; 261(2): 430-7, 1999 Apr.
Article
em En
| MEDLINE
| ID: mdl-10215853
ABSTRACT
SiR-FP60, the monomeric form of the Escherichia coli sulfite reductase flavoprotein component (SiR-FP), has been analysed by 31P-NMR spectroscopy. This protein was reported previously as a reliable simplified model for native SiR-FP [Zeghouf, M., Fontecave, M., Macherel, D., & Covès, J. (1998) Biochemistry 37, 6117-6123]. SiR-FP60 was examined in its native form, as a complex with NADP+ and after monoelectronic reduction either with NADPH or dithionite. In these latter cases, the stabilized FMN semiquinone radical offers a natural and internal paramagnetic probe. The paramagnetic effect of added manganese was also studied. In each case, the NMR parameters were extracted from digitalized data by a deconvolution procedure and compared with those obtained previously with cytochrome P450 reductase. Evolution of the NMR parameters and of calculated relaxation rate constants upon biochemical modifications of SiR-FP60 led us to propose that the reactive center is more compact than the one of cytochrome P450 reductase, with the redox components, FMN, FAD and NADPH, in a tighter spatial arrangement, close to the protein surface. This underlies some subtle differences between the two proteins for which a very similar overall structure is likely considering their common genetic origin and common operating cycle.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Escherichia coli
/
Oxirredutases atuantes sobre Doadores de Grupo Enxofre
/
Flavoproteínas
Idioma:
En
Revista:
Eur J Biochem
Ano de publicação:
1999
Tipo de documento:
Article
País de afiliação:
França