The NADP-reducing hydrogenase from Desulfovibrio fructosovorans: functional interaction between the C-terminal region of HndA and the N-terminal region of HndD subunits.
Biochim Biophys Acta
; 1556(2-3): 217-25, 2002 Dec 02.
Article
en En
| MEDLINE
| ID: mdl-12460679
The hndABCD operon from Desulfovibrio fructosovorans encodes an uncommon heterotetrameric NADP-reducing iron hydrogenase. The presence of a [2Fe-2S] cluster likely located in the C-terminal region of the HndA subunit has already been revealed. We have cloned and expressed the truncated hndA gene in Escherichia coli to isolate the structural [2Fe-2S] module. Optical and EPR spectra are found identical to that of the native HndA subunit and the midpoint redox potential (-385 mV) is similar to that of the native protein (-395 mV). These results clearly demonstrate that the C-terminal region of HndA is a structurally independent [2Fe2S] ferredoxin-like domain. In the same way, the N-terminal domain of the HndD subunit was overproduced in E. coli and characterized. The presence of a [2Fe-2S] cluster was evidenced by optical spectroscopy. The midpoint redox potential (-380 mV) of this domain was found very close to that of the truncated HndA subunit but the EPR properties were significantly different. The various EPR properties allowed us to observe an electron exchange between the two [2Fe-2S] ferredoxin-like domains of the HndA and HndD subunits. Moreover, domain-domain interactions, observed by far-western experiments, indicate that these subunits are direct partners in the native complex.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Oxidorreductasas
/
Desulfovibrio
Idioma:
En
Revista:
Biochim Biophys Acta
Año:
2002
Tipo del documento:
Article
País de afiliación:
Francia
Pais de publicación:
Países Bajos