Alpha sheet

The conundrum is resolved by realizing that the alphaL region comprises two overlapping areas, here called γL and αL, which should be considered separately.

[8] Alpha-sheet conformations have been observed in crystal structures of short non-natural peptides, especially those containing a mixture of L and D amino acids.

[14][15] Xu,[16] using atomic force microscopy, has shown that formation of amyloid fibers is a two-step process in which proteins first aggregate into colloidal spheres of ≈20 nm diameter.

The formation of these linear chains appears to be driven by the development of an electrostatic dipole in each of the colloidal spheres strong enough to overcome coulomb repulsion.

[4] Molecular dynamics simulations of the mutant protein reveal that the region around the mutation assumes an alpha strand conformation.

This process has also been observed in simulations of transthyretin[19] and implicated as occurring naturally in certain protein families by examination of their dihedral angle conformations in crystal structures.

[22] Evidence employing retro-enantio N-methylated peptides, or those with alternating L and D amino acids, as inhibitors of beta-amyloid aggregation is consistent with alpha-sheet being the main material of the amyloid precursor.