Desulfoferrodoxin: a modular protein

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• 作者：Carla Ascenso ; Frank Rusnak ; In¨ºs Cabrito ; Maria J. Lima ; Stephen Naylor ; Isabel Moura and Jos¨¦ J.G. Moura
• 刊名：Journal of Biological Inorganic Chemistry
• 出版年：2000
• 出版时间：November 2000
• 年：2000
• 卷：5
• 期：6
• 页码：720-729
• 全文大小：357 KB

文摘

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(N)-His)3(N'-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.