Figure 3.

(a) Superposition of the mean NMR structures of the polypeptide segment 124–227 in bPrP(23–230) (violet) and bPrP(121–230) (green). A spline function was drawn through the C^α positions. The variable radius of the cylindrical rods is proportional to the mean global backbone displacement per residue (43), as evaluated after superposition for best fit of the atoms N, C^α, and C′ of the residues 125–227 in the two bundles of 20 energy-minimized conformers used to represent the solution structures (29). (b–d) Superposition of the segment 125–227 in bPrP(121–230) (green) with the corresponding residues in hPrP(121–230) (b; orange), mPrP(121–231) (c; yellow), and shPrP(90–231) (d; pink), respectively.