FIGURE 2.

Crossing the inner envelope membrane of chloroplasts via the TIC complex. The counterpart of the outer channel protein is the IEM protein Tic110 which is a functional dimer. Two hydrophobic domains anchor the protein into the IEM whereas further eight amphipathic helices are involved in the channel formation. Tic40 is supposed to interact with Tic110 with its Sti1 domain and acts further as a scaffold for stromal chaperones. Controversial, the 1MDa-complex depicted on the right side comprises atTic20 as the channel protein, atTic56 embedded in the complex, atTic100 located at the IMS and the plastid encoded Ycf1 (atTic214) with its six transmembrane domains and a large stromal C-terminus.