Figure 2.

Structures of human wild-type and mutant SMN YG-box (residues 255–281) tetramers. Ser266 in the wild-type peptide and Pro266 in the mutant peptide are shown in ball-and-stick representations. Predicted solution structures of the wild-type YG-box tetramer (A, golden/wheat) and the mutant tetramer (B, blue/cyan). Root mean squared fluctuations of the helix backbones in the wild-type YG-box (C) and the mutant YG-box (D) from molecular dynamics simulations. The vertical dotted lines indicate the location of the substitution. The error bars indicate standard deviations. A kink is noticeable in the mutant peptide but not in the wild-type peptide.