Redox behaviour of the haem domain of flavocytochrome c3 from Shewanella frigidimarina probed by NMR.
FEBS Lett
; 578(1-2): 185-90, 2004 Dec 03.
Article
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| MEDLINE
| ID: mdl-15581639
ABSTRACT
Flavocytochrome c3 from Shewanella frigidimarina (fcc3) is a tetrahaem periplasmic protein of 64 kDa with fumarate reductase activity. This work reports the first example of NMR techniques applied to the assignment of the thermodynamic order of oxidation of the four individual haems for such large protein, expanding its applicability to a wide range of proteins. NMR data from partially and fully oxidised samples of fcc3 and a mutated protein with an axial ligand of haem IV replaced by alanine were compared with calculated chemical shifts, allowing the structural assignment of the signals and the unequivocal determination of the order of oxidation of the haems. As oxidation progresses the fcc3 haem domain is polarised, with haems I and II much more oxidised than haems III and IV, haem IV being the most reduced. Thus, during catalysis as an electron is taken by the flavin adenosine dinucleotide from haem IV, haem III is eager to re-reduce haem IV, allowing the transfer of two electrons to the active site.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Succinato Deshidrogenasa
/
Proteínas Bacterianas
/
Shewanella
/
Grupo Citocromo c
/
Hemo
Idioma:
En
Revista:
FEBS Lett
Año:
2004
Tipo del documento:
Article
País de afiliación:
Portugal