Figure 6.

Membrane targeting of RNCs with reconstituted proteoliposomes. (A) pPL86 was synthesized in the wheat germ system. Where indicated, SRP and increasing volumes of a mock translation mixture (given in fold excess over the mixture containing the RNCs) were added before addition of reconstituted proteoliposomes containing the Sec61p complex (Sec61p) and the SRP receptor (SR). Membrane targeting was tested with a protease protection assay. Lane 1 shows the undigested pPL86 (total), all other samples were treated with proteinase K. The band designated with an asterisk is the ribosome-protected fragment of about 30 residues. (B) An experiment similar to that in A was carried out with proteoliposomes containing only the Sec61p complex.