a highly stable plastidic-type ferredoxin-nadp(h) reductase in the pathogenic bacterium leptospira interrogans一个高度稳定的plastidic-type ferredoxin-nadp(h)还原酶在细菌致病性钩端螺旋体interrogans.pdfVIP

A Highly Stable Plastidic-Type Ferredoxin-NADP(H) Reductase in the Pathogenic Bacterium Leptospira interrogans ´ ´ Daniela L. Catalano-Dupuy, Matıas A. Musumeci, Arleth Lopez-Rivero, Eduardo A. Ceccarelli* ´ ´ ´ Molecular Biology Division, Instituto de Biologıa Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquımicas y Farmaceuticas, Universidad Nacional de Rosario, Rosario, Argentina Abstract Leptospira interrogans is a bacterium that is capable of infecting animals and humans, and its infection causes leptospirosis with a range of symptoms from flu-like to severe illness and death. Despite being a bacteria, Leptospira interrogans contains a plastidic class ferredoxin-NADP(H) reductase (FNR) with high catalytic efficiency, at difference from the bacterial class FNRs. These flavoenzymes catalyze the electron transfer between NADP(H) and ferredoxins or flavodoxins. The inclusion of a plastidic FNR in Leptospira metabolism and in its parasitic life cycle is not currently understood. Bioinformatic analyses of the available genomic and proteins sequences showed that the presence of this enzyme in nonphotosynthetic bacteria is restricted to the Leptospira genus and that a [4Fe-4S] ferredoxin (LB107) encoded by the Leptospira genome may be the natural substrate of the enzyme. Leptospira FNR (LepFNR) displayed high diaphorase activity using artificial acceptors and functioned as a ferric reductase. LepFNR displayed cytochrome c reductase activity with the Leptospira LB107 ferredoxin with an optimum at pH 6.5. Structural stability analysis demonstrates that LepFNR is one of the most stable FNRs analyzed