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Figure 4
Alternative conformations of the N-terminal segment of Arc1p-N are determined by crystal-packing constraints. Tetramers stack on top of each other along the z axis (a). Conformation 1 (brown) (b) and 2 (green) (c) represent two different ways of domain swapping of the N-terminal α-helix between conformationally corresponding monomers from neighbouring tetramers. Conformation 3 (grey) represents the `default' conformation adopted in the absence of packing constraints. The `default' conformation 3 is shown as a yellow and green Cα trace superimposed on the conformers 1 in (b) and 2 in (c). See text for explanation. |