Toc75 and t75-fusion proteins used for the study.

(A) Toc75 precursor (t75-m75) carries an N-terminal extension (t75), which comprises n75 and c75, for correct targeting to the chloroplast envelope. Removals of n75 and c75 by SPP and Plsp1 yield the intermediate (c75-m75) and mature form (m75), respectively. Primary sequences of part of c75 and its variants are shown above the diagram. (B) A diagram of four chimeric proteins used in the study.