ITPK1 (Inositol Tetrakisphosphate 1-Kinase), Fig. 3

Catalytic activities of mammalian ITPK1: rationalization of the structural determinants of the ligands. The figure depicts the proposal that there are three modes of binding of inositol phosphates to mammalian ITPK1 (i.e., modes 1, 2, and 3), which facilitate 1-kinase, 6-kinase, and 5-kinase activities, respectively. The phosphorylation sites are marked with a yellow circle. Groups that are stereochemically equivalent in all three of these proposed binding modes are colored in red; these are highly likely to drive ligand orientation. Groups that are stereochemically equivalent in two of these three proposed binding modes are colored in green; these may also drive ligand orientation. Adapted from Riley et al. (2006)