Figure 7.

Interaction of Recombinant cpSRP54 Constructs and Chloroplast Ribosomes.

(A) to (I) Recombinant His-tagged mature cpSRP54 (A), cpSRP43 (B), and the indicated cpSRP54 constructs (see [C] to [I]) were incubated with chloroplast ribosomes and loaded onto a Suc gradient. After ultracentrifugation, the gradient fractions were analyzed immunologically using antibodies against the His-tag (α-His) and the ribosomal protein uL4 (α-uL4). Sucrose density gradient centrifugation of the recombinant proteins in the absence of ribosomes was used as negative controls. cpSRP54M, M-domain (amino acids 371 to 564); cpSRP54NG, NG-domain (amino acids 77 to 370); Cterm, C-terminal tail region (amino acids 530 to 564).