The cpTatC non-conserved stromal domain is not necessary for cpTatC localization. (a) Scheme illustrating deletion of the cpTatC non-conserved region (NC region). Numbers above constructs represent the number of amino acids from the translation start site. (b) Radiolabeled pcpTatC and SSUtpΔNCcpTatC were incubated with chloroplasts in a protein import assay (Experimental Procedures) for 20 minutes. Chloroplasts were treated with 100 μg/mL thermolysin, re-purified, washed, lysed, and fractionated into stroma and membranes. Translation product (Tp) equivalent to 5% of each assay, chloroplasts (Cp), stroma (S), membranes (M), and thermolysin-treated membranes (+T) were analyzed using SDS-PAGE and fluorography. Membranes were also dissolved in 1% digitonin and analyzed using Blue Native PAGE and fluorography. The positions of molecular weight markers (Mr), or monomeric (440 kD) and dimeric (880 kD) ferritin for BN-PAGE, are shown at left.