Video 3. The hand-over-hand model for substrate translocation.
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DOI: 10.7554/eLife.25754.014
Interpolation between states where each subunit sequentially goes through the different possible positions in the helix. Each promoter’s pore loop binds a section of substrate at the top of the helix and escorts that section toward the bottom of the image through five steps. On the sixth step the protomer releases the substrate and becomes the seam protomer, moving up and away from the central pore before reengaging at the top of the substrate. An arbitrary subunit is marked in green to help maintain orientation. The structures are shown as ribbon diagrams (left) and Cα positions for the pore loop residues (right). Scale bars, 25 Å. Please view video as loop.