The extremophilic Andean isolate Acinetobacter sp. Ver3 expresses two ferredoxin ‐NADP+ reductase isoforms with different catalytic properties

Extremophilic microorganisms are an invaluable source of new biomolecules with unique characteristics. The genome ofAcinetobacter sp. Ver3 isolated from high-altitude Andean lakes encodes two ferredoxin/flavodoxin-NADP+ oxidoreductases, FPR1ver3 and FPR2ver3, which display kinetic and spectroscopic characteristics similar to other prokaryotic FPRs and contribute to the bacterial protection against oxidative stress. Ferredoxin/flavodoxin-NADPH reductases (FPRs) catalyze the reversible electron transfer between NADPH and ferredoxin/flavodoxin. TheAcinetobacter sp. Ver3 isolated from high-altitude Andean lakes contains two isoenzymes, FPR1ver3 and FPR2ver3. Absorption spectra of these FPRs revealed typical features of flavoproteins, consistent with the use of FAD as a prosthetic group. Spectral differences indicate distinct electronic arrangements for the flavin in each enzyme. Steady-state kinetic measurements show that the enzymes display catalytic efficiencies in the order of 1 –6 μm−1·s−1, although FPR1ver3 exhibited higherkcat values compared to FPR2ver3. When flavodoxinver3 was used as a substrate, both reductases exhibited dissimilar behavior. Moreover, only FPR1ver3 is induced by oxidative stimuli, indicating that the polyextremophile Ver3 has evolved diverse strategies to cope with oxidative environments.
Source: FEBS Letters - Category: Biochemistry Authors: Tags: Research Article Source Type: research