Figure 3.

The endoplasmic reticulum-targeted protein PPL binds cpSRP posttranslationally when fused behind an 18-aa region of LHCP. In vitro-translated PPL (A) or chimeric proteins with regions of LHCP fused at the amino terminus of PPL (B–D) were assayed for their abilities to form transit complex (arrowheads) as described in the legend to Fig. 2. The amino acid composition of the PPL signal sequence and the composition of signal sequences from chimeric proteins are shown to the left. The H domain for each construct is underlined. For chimeric proteins, the amino acids derived from LHCP (indicated in the rectangles) and from the PPL signal sequence are shown.