Figure 7.

The in-vivo redox state of Mia40 is partially reduced. (A) The pathway for disulphide bond formation in the IMS. Reduced substrates are oxidized by Mia40 which in turn is re-oxidized by Erv1. From Erv1 electrons can be passed on directly to oxygen or to respiratory chain complex IV. (B) In-vivo redox state of Mia40 in wild-type yeast cells. Cells were precipitated with TCA. The resulting pellet was resuspended in a buffer containing 50 mM NEM. The samples were analysed on non-reducing SDS–PAGE followed by immunoblotting against Mia40. SS; steady state. Reported values are the mean of three independent experiments. Error bars are the means±s.d. (C) Erv1 levels in cells that express Erv1 under the control of a regulatable promoter. Cells were grown either in galactose or in glucose to raise or lower cellular Erv1 levels, respectively. Erv1 levels were tested by western blot analysis. (D) Redox state of Mia40 in cells with different Erv1 levels. As (B), except that cells expressed Erv1 under the control of a regulatable promoter. Cells were grown either in galactose or in glucose to raise or lower cellular Erv1 levels, respectively. Reported values are the mean of three independent experiments. Error bars are the means±s.d. (E) Redox state of Mia40 in Δrip1 and Δcox17 cells in the presence of 20 or 1% oxygen. As (B), except that the experiment was performed with Δrip1 and Δcox17 cells in the presence of different oxygen concentrations. The experiments have been performed three times independently. Error bars are the means±s.d. Figure source data can be found with the Supplementary data.