Amino acid propensities Large aromatic residues (tyrosine, phenylalanine, tryptophan) and β-branched amino acids (threonine, valine, isoleucine) are favored to be found in β-strands in the middle of β-sheets. Different types of residues (such as proline) are likely to be found in the edge strands in β-sheets, presumably to avoid the "edge-to-edge" association between proteins that might lead to aggregation and amyloid formation.
Amino acid propensities Large aromatic residues (tyrosine phenylalanine, tryptophan) and β-branched amino acids (threonine valine, isoleucine) are favored to be found in β-strands in the middle of β-,sheets. Different types of residues (such as proline) are likely to be found in the edge strands ,in β-sheets, presumably to avoid the "edge-to-edge" association between proteins that might lead to aggregation and amyloid formation.