Fig. 2.

Cox26 stabilizes III–IV supercomplexes. (A) BNE of digitonin-solubilized mitochondrial complexes from wild type (W303–1A) and Cox26 null mutant strain (Δcox26) grown under identical conditions in YPD and YPL. Individual or supercomplex associated complex IV was detected by a specific in-gel complex IV activity stain [12]. Decreased amounts of supercomplexes were detected in the mutant strain in both conditions with even less stability in cells grown in glucose (upper panel). The same gel was stained with Coomassie to show complex V as loading control (lower panel). (B) 2-D Tricine-SDS-PAGE of complexes from wild type and Δcox26 strain using 13% acrylamide gels revealed identical subunit pattern for complexes III and IV. Decoration with an antibody against Cox26 shows presence of Cox26 in III–IV supercomplexes in wild type mitochondria. Assignment of protein complexes: according to Fig. 1. BHM, bovine heart mitochondria as native mass ladder.