Figure 6. Geometrical rearrangements triggered by tilted monomers.

(a,b) Representative pentamers of AaLS-wt, AaLS-neg and AaLS-13. Two of the five monomers for each structure are shown in green and the rest in grey. Views around the (pseudo) five-fold rotational symmetry axes (a) and the corresponding side views parallel to the axes (b) are shown. Residues 83, 86, 120 and 123, which were mutated to glutamates by design, are shown as red spheres and boxed. For AaLS-13, residues 28, 52, 112, 115, 118, 127 and 131, which were mutated during directed evolution, are shown as coloured spheres. Red and magenta spheres indicate the negatively charged residues that were introduced. The wedge-like shapes of the pentamers are schematically highlighted by dotted lines. (c) Representative orientation of two adjacent pentamers in AaLS-wt, AaLS-neg and AaLS-13, respectively. Angles between the adjacent local (pseudo) five-fold axes are shown.