Desulfoferrodoxin: a modular protein.
The gene encoding the non-heme iron-containing desulfoferrodoxin from Desulfovibrio vulgaris was cloned in two fragments in order to obtain polypeptides corresponding to the N- and C-terminal domains observed in the tertiary structure. These fragments were expressed in Escherichia coli, purified to homogeneity and biochemically and spectroscopically characterized. Both recombinant fragments behaved as independent metal-binding domains. The N-terminal fragment exhibited properties similar to desulforedoxin, as expected by the presence of a Fe(S-Cys)4 metal binding motif. The C-terminal fragment, which accommodates a Fe(Nepsilon-His)3(Ndelta-His)(S-Cys) center, was shown to have properties similar to neelaredoxin, except for the reaction with superoxide. The activities of desulfoferrodoxin and of the expressed C-terminal fragment were tested with superoxide in the presence and absence of cytochrome c. The results are consistent with superoxide reductase activity and a possible explanation for the low superoxide consumption in the superoxide dismutase activity assays is proposed.
Ascenso
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Depatamento de Química, Centro de Química Fina e Biotecnologia, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.
Rusnak
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Cabrito
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Lima
M J
MJ
Naylor
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Moura
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Moura
J J
JJ
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D004269:DNA, Bacterial; D016969:Desulfovibrio vulgaris / Q000235:genetics; D005288:Ferredoxins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D013482:Superoxide Dismutase / Q000378:metabolism
D017931:DNA Primers; D004269:DNA, Bacterial; D005288:Ferredoxins; C066602:desulfoferrodoxin; D013482:Superoxide Dismutase