Fig. 4: Crystal structures of IP3K-ligand complexes.

A zoom of IP3K-ligand structures showing the ligand recognition site in 3-substituted analogues (5–7). Color code is the same as Fig. 3. Arrows link IP3K-substrate complexes with their related IP3K-product complexes. The IP3K complex with the expected product from the atypical substrate 5-s has been formed by crystal soaking with 5-p. IP3K crystal complexes with products 6a–p and 7a–p have been obtained by crystal soaking with the substrates 6a–s and 7a–s.