Figure 1.

Reduction of the mitoNEET [2Fe-2S] clusters by FMNH₂ under aerobic and anaerobic conditions. A and B, MitoNEET (containing 10 μm [2Fe-2S] clusters) was incubated with FMN (0.1 μm) and NADH (60 μm) under anaerobic (A) and aerobic (B) conditions. Fre (0.1 μm) was then added to the solutions to initiate the reaction. UV-visible absorption spectra were taken every 80 s after addition of Fre for 560 s. Absorption peaks at 455 nm and 540 nm represent the oxidized mitoNEET [2Fe-2S] clusters. O.D., optical density. C, time courses of NADH oxidation in the incubation solutions containing mitoNEET, Fre, and FMN under anaerobic (closed circles) or aerobic (open circles) conditions. The amount of NADH in the incubation solutions was measured from the absorption peak at 340 nm after subtracting the absorption of proteins in the incubation solutions. D, the same as in B, except no mitoNEET was included. The data are representative of three independent experiments.