PROTEIN TRANSLOCATION INTO AND ACROSS THE CHLOROPLASTIC ENVELOPE MEMBRANES

Post-translational protein import into chloroplasts follows a common r oute characterised by the need for nucleoside-triphosphates at various steps and two distinct protein import machineries at the outer and in ner envelope membrane, respectively. Several subunits of these complex es have been elucidated. In contrast, protein translocation into the c hloroplastic outer envelope uses distinct and various but poorly chara cterised insertion pathways. A topological framework for single-membra ne spanning proteins of the chloroplastic outer envelope is presented.