Fig. 6
From: Comprehensive analysis of the Co-structures of dipeptidyl peptidase IV and its inhibitor
Two specific water O atoms close to inhibitors (red spheres). Both of the two water O atoms were found in 108 inhibitor-bound units. When superimposed so that the RMSD targeting Cα atoms in DPP-4 (residue 41–764) would be minimized based on 1X70_A, water O atoms in the unit were simultaneously superimposed. The carbon skeleton of inhibitors is shown with green line. O, N and halogen atoms are colored red, blue and pale cyan, respectively. The DPP-4 structure was obtained from the coordinates of PDB ID 1X70. The distances between inhibitors and the first specific water O atoms (No. 1) are shown with dashed cyan lines. The distances between inhibitors and the second specific water O atoms (No. 2) are shown with dashed magenta lines. The distances between the two water O atoms and His126, Glu205, Gul206, Ser209 or Arg669 are shown with dashed bold yellow line. Phe357 (yellow area) forms a large wall at the S2 subsite