FIGURE 3.

Oep37 can be imported in vitro into chloroplasts and mitochondria. Radiolabeled Oep37 was incubated for 30 min at RT with either isolated pea chloroplasts (A) or isolated mitochondria (B). Membrane insertion was assayed by the resistance to carbonate treatment (CO₃²⁻) in the presence or absence of Triton X-100 (Tx). An aliquot (5%) of the translation product (TP) used for each import reaction was loaded as control. The bands corresponding to Oep37 are indicated with an arrowhead. C, purity of the isolated mitochondria (M) or chloroplasts (C) was monitored by analyzing 10 μg of total organellar protein by SDS-PAGE followed by immunodecoration, using organelle-specific antibodies (α-VDAC for mitochondria and α-Toc75 for chloroplasts). The bands corresponding to the marker proteins are indicated with an arrowhead, whereas unspecific bands resulting from cross-reactivity of the antibodies are marked with an asterisk.