Figure 7.

Summary of the conserved water molecules in the active site cleft. (Left) The conserved active site region of five different closed conformation crystal structures (I–IV) are superimposed. ASCWs present in all (or most) of the structures (a–f) and LSCWs that are present when all or part of one of the ligands is absent (g-m) are shown. The residues Glu-91, Lys-72, Glu-127, Glu-121, Val-123, and Tyr-330 from the enzyme and a section of the inhibitor peptide, residues PKI(18–22), and water molecules in the nucleotide binding pocket from the five structures are color-coded according to Fig. 5 and Table 1. (Right) Summary of the positions of the ASCWs and LSCWs.