FIGURE 4.

Model of hIAPP fibril structure. A, a typical hIAPP peptide incorporated in the fibril, viewed along the fibril axis. B, the same peptide viewed along an axis orthogonal to the fibril axis, showing the stagger of the two β-strands of the peptide. C, a section of the structural model showing the stagger of the peptides (shown as blue, green, and orange ribbons; the relationship of blue-colored peptides is indicated). D, rotation of the structural model with the axes of β-strands orthogonal to the fibril. E, a structural model containing 101 peptides showing a turn of the left-handed helix of ∼90° between the centers of the red boxes. The helix has an average pitch of 440 Å.