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

CATALANO DUPUY, D. L.; CECCARELLI, E. A.

Mar del Plata, Buenos Aires

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

Ferredoxin-NADP(H) reductases (FNR) are flavoenzymes thatdeliver NADPH or low potential one-electron donors (ferredoxin,flavodoxin) to redox metabolisms in plastids, mitochondria andbacteria. There are differences in catalytic efficiencies among themembers of the FNR family. Whereas plant FNRs display turnovernumbers related to the needs of the photosynthesis, bacterialreductases are much less active. It is not known how this catalyticimprovement was accomplished but probably was obtained bysubtle changes in the protein structure and FAD conformation.Wefound that FNR from (LepFNR), aparasitic bacterium of animals and humans, belongs to the plastidicclass of FNRs at variance of all other bacterial enzymes. Thestructural and biochemical characteristics of plant FNRs revealedfor LepFNR support the notion of a putative lateral gene transferoffering evolutionary advantages. Looking for thephysiological substrate of this reductase we cloned two ferredoxingenes (LFd1 and LFd2) from the bacterium genome.We found thatLFd1 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 beimplicated in the non-mevalonate dependent isopronoidbiosynthesis pathway, a possible target for antibiotic development.