  Protein function depends on both protein structure and amino acid (aa)
sequence. Here we show that modular features of both structure and function can
be quantified from the aa sequences alone for the small (40,42 aa)
plaque-forming amyloid beta fragments. Some edge and center features of the
fragments are predicted. Contrasting results from the second order
hydropathicity scale based on evolutionary optimization (self-organized
criticality) and the first order scale based on complete protein (water-air)
unfolding show that fragmentation has mixed first- and second-order character.
