A 2[4FE-4S] ferredoxin is substrate of ferredoxin-NADP+ reductase from Leptospira interrogans

LOPEZ-RIVERO, A; MUSUMECI, M. A.; CECCARELLI, E. A.; CATALANO DUPUY, D. L.

Potrero de los Funes, San Luis

Congreso; XLVII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2011

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

potential which act as electron donors in various metabolicpathways. They can be grouped in three distinct families, the plantand mammalian type [2Fe–2S], the thioredoxin-like [2Fe-2S] andthe 2[4Fe-4S] ferredoxins, first isolated from anaerobic bacteria.The latter may differ in cluster type (3Fe or 4Fe), number (one ortwo), and length of polypeptide chain. Ferredoxins can be substratesof ferredoxin-NADP+ reductases (FNR) in redox metabolisms inmitochondria, plastids and bacteria. We have identified and cloned a2[4Fe-4S] ferredoxin (LFd2) from Leptospira interrogans, aparasitic bacterium of animals and humans. We succeeded inexpressing and purifying the recombinant protein with its Fe-Scluster properly bound, by co-expressing the biogenesis iron-sulfursystem (ISC) from Escherichia coli. An O -free atmosphere was 2required during the purification protocol. LFd2 displayed spectralsimilarities with typical 2[4Fe-4S] ferredoxins. We were able tomeasure cytochrome c reductase activity with L. interrogans FNRand LFd2. Our results suggest that electron transfer between thereductase and LFd2 is optimal at pH 6,5 and low salt concentration.Our studies show that in L. interrogans a plastidic type FNRexchanges electrons with a bacterial type ferredoxin, process whichhas not been previously observed in nature.