Figure 4. Lack of supercomplexes impairs electron transport from CIII to CIV .

• A, B
  Spectrophotometric measurement of Cyt c oxidase (CIV; A) and NADH Cyt c reductase (CIII; B) activities in solubilized mitochondrial extracts. Mitochondria were isolated from cells expressing the wild‐type form of Cor1 (Cor1^WT) or the mutant Cor1^{N63A, N187A, D192A, V189A, Y65A, L238A, K240A} (Cor1**).
• C, D
  Polarographic measurement of KCN‐sensitive oxygen consumption, driven by NADH (C) or succinate + glycerol‐3-phosphate (G3P; D) in isolated coupled mitochondria of indicated strains. Measurements were performed in the absence (basal respiration) or presence (phosphorylating condition) of ADP.
• E
  Respiratory control ratio calculated from polarographic measurements of KCN‐sensitive oxygen consumption driven by NADH and succinate + glycerol‐3-phosphate (G3P) in isolated coupled mitochondria of indicated strains.
• F, G
  Polarographic measurement of KCN‐sensitive oxygen consumption driven by NADH in mitoplasts in the absence (endog. Cyt c) or presence (+ exog. Cyt c) of exogenous oxidized Cyt c. NADH oxidation (E) and the calculated ratio +Cyt c/−Cyt c of substrate oxidation (F) are visualized.

Data information: Mean (square) ± s.e.m., median (center line) and single data points are depicted. Two‐tailed independent sample t‐tests were used to analyze data from at least three individual mitochondrial isolations (n ≥ 3 biological replicates), For (A, B, and F endog. Cyt c), Welch correction was performed, and for (E Succinate + G3P), a two‐tailed Mann–Whitney U test was applied. Significances are given as: n.s.: not significant (P ≥ 0.05), *P < 0.05, **P < 0.01, and ***P < 0.001. A detailed description of statistical analyses performed is given in Table EV6.