Fig. 3

Side chain variations of DPP-4. Sixteen residues in the inhibitor binding area are labeled (red columns). Thirteen residues (Arg125, Tyr 631, Tyr 662, Tyr 666, Ser209, Val656, Val711, Asn710, Glu205, Glu206, His740 and Phe357 and Trp659) have their side chain variations below the average variation of the equivalent amino acids (dashed black line). Specific atoms that are positioned furthest from the main chain were calculated to be the variation. The graph shows the variations for each amino acid and they are listed in the order of the exposed surface area. The vertical axis on the left is the exposed surface area (blue line graph) and the vertical axis on the right is the variation value (green bar and red column graph). The variations of the two Arg Nη atoms, the two Glu Oε atoms and the two Val Cγ atoms are averaged, respectively. a Arg Nη atom, b Tyr Oη atom, c Ser Oγ atom, d Val Oγ atom, e Asn Nδ atom, f Glu Oε atom, g His Nε atom, h Phe Cζ atom and i Trp Cη atom