A highly efficient Ferredoxin-NADP(H) reductase in the redox metabolism of Leptospira interrogans.

CATALANO DUPUY, DANIELA L.; CECCARELLI, EDUARDO A.

Mar del Plata, Buenos Aires. ARGENTINA

Congreso; XLIII Reunión Anual de la Sociedad Argentina de investigación en Bioquímica y Biología Molecular (SAIB); 2007

Sociedad Argentina de investigación en Bioquímica y Biología Molecular (SAIB)

Ferredoxin-NADP(H) reductases (FNR) are flavoenzymes that deliver NADPH or low potential one-electron donors (ferredoxin, flavodoxin) to redox metabolisms in plastids, mitochondria and bacteria. There are differences in catalytic efficiencies among the members of the FNR family. Whereas plant FNRs display turnover numbers related to the needs of the photosynthesis, bacterial reductases are much less active. It is not known how this catalytic improvement was accomplished but probably was obtained by subtle changes in the protein structure and FAD conformation.We found that FNR from (LepFNR), a parasitic bacterium of animals and humans, belongs to the plastidic class of FNRs at variance of all other bacterial enzymes. The structural and biochemical characteristics of plant FNRs revealed for LepFNR support the notion of a putative lateral gene transfer offering evolutionary advantages. Looking for the physiological substrate of this reductase we cloned two ferredoxin genes (LFd1 and LFd2) from the bacterium genome.We found that LFd1 displays sequence and spectral similarities with [2Fe-2S] ferredoxins with tiorredoxin-like folding whereas LFd2 is a [4Fe-4S] ferredoxin. Our previous studies indicate that these Fds may be implicated in the non-mevalonate dependent isopronoid biosynthesis pathway, a possible target for antibiotic development.