Figure 6.

Ionophores abolish the luminal localization of OE17 in both chromoplasts and chloroplasts. Import of radiolabeled pOE17 into isolated chromoplasts (containing 0.4 μg chlorophyll/mg protein) and chloroplasts was performed in the absence or presence (+N/V) of nigericin and valinomycin at final concentrations of 0.5 and 1.0 μm, respectively, as described in Methods. Following import, total plastids were recovered (lanes T) and fractionated into stromal (lanes S) and membrane fractions, and the membranes were treated with protease (lanes MP). One microliter of radiolabeled precursor (lanes tp) and 15 μL of each sample (representing 7.5 μL of the original radiolabeled precursor added to the import reaction) were analyzed by 12.5% SDS-PAGE and fluorography. p, pOE17; i, iOE17; m, mOE17.