Figure 6 - full size

 

Figure 6.
Switching mechanism. Alternative conformations of the N-terminal (orange) and C-terminal (blue) amino acids in the 3-α and 4β+α folds. The critical switch amino acid occurs at position 45 (red). Also depicted are the hydrophobic packing of the N- and C-terminal amino acids in the core of the 4β+α fold.