Fig. 7: Effect of V127 polymorphism on the amplitude of PrP ms dynamics (R_ex).

The sidechains of residues which experience altered ms dynamics in V127/M129 PrP, relative to G127/M129 PrP are shown (Fig. 6c), with varying width of backbone and colour. Residues showing increased R_ex values in the V127 variant, such as G131, R164, E168 and Q172, are coloured red, with those showing a reduction, such as Y218, are coloured blue. Those residues for which a comparison is not possible, due to absence of data are not coloured. The orientation of R164 and E168 sidechains in G127/M129 PrP are shown in yellow²⁹, illustrating the loss of hydrogen bonding in V127/M129 PrP, caused by a steric clash between V127 and R164 sidechains in the V127 variant. Also shown is the hydrogen bond between Y169 and D178, showing the close association between the β2-α2 loop and another residue which has a key effect on the aetiology of human prion disease.