Figure 6: Combination of four different interaction modes forms a linear strand.
From: The four-transmembrane protein IP39 of Euglena forms strands by a trimeric unit repeat
(a) A schematic diagram showing the arrangement of the IP39 protomers as shown in Fig. 4f. The four coloured rectangles distinguish the different pairs of interacting molecules. (b–e) The respective pairs of molecules shown in a are extracted (upper panels) and the corresponding EM density maps are represented by transparent surfaces with the fitted model helices superimposed (lower panels). The maps of Mol1-Mol2 (b), Mol2-Mol3 (c) and Mol3-Mol1 (d) are viewed perpendicular to the membrane planes from their intracellular sides, and the map of Mol1-Mol1 (e) is viewed slightly diagonally from the intracellular side. The black open arrow indicates the overlaid area of the Mol3 protrusion on the cytosolic region of Mol2. The surface colour codes are the same as in Fig. 4a. The black bars represent 10 Å.
