FIGURE 4.

Import of CA domain subunits and 20.9-kDa subunit into wild type Arabidopsis mitochondria. A, [³⁵S]Met-labeled precursors (P) were incubated with mitochondria (M) for 60 min with and without PK treatment and were separated by SDS-PAGE. B, [³⁵S]Met-labeled precursors were incubated with fresh mitochondria, following which proteins from PK-treated mitochondria were separated by BN-PAGE. Radiolabeled bands aligned to a Coomassie-stained BN-polyacrylamide gel of the same material and the positions of complexes and subcomplexes are shown. Molecular masses of complexes are reported against standardized masses (23). *, location of 200–300-kDa complex I subcomplexes. The control lane is an equivalent import assay with the ϵ subunit of ATP synthase (At1g51650), which does not readily get incorporated into complexes and serves as a reference for radiolabeling patterns on SDS-polyacrylamide gel images.