Figure 4.

Types of β-turns. Based on 3 empirically characterized GIGG, GAGG, and TIHG flap-like β-hairpin loops, and 3 prediction GIGG and GANG models, the β-turns differ from each other based on the orientation the "Phi" and "Psi" torsional angles of the peptide bond between residues in "i+1" and "i+2" (indicated with curved arrows). Additional differences based on the properties of the residues in the position "i+1" are also observed (in circles). Chains were colored according to the physiochemical properties of amino acids. Hydrophobic residues are colored grey, acidic residues and relatives are yellow, and basic residues are in blue.