Solution Studies and Crystal Structures of Heteropolynuclear Potassium/Copper Complexes with Phytate and Aromatic Polyamines: Self-Assembly through Coordinative and Supramolecular Interactions

Structural Insight on Supramolecular Polyion Salts: Inositol Hexaphosphate Enclosed in Cationic Macrocyclic Clusters

Supramolecular macrocyclic forces have been used to trap phytate, myo-inositol-1,2,3,4,5,6-hexakisphosphate, a key bioanion with multiple roles in metabolic processes. Due to the complex chemistry of six multivalent phosphates surrounding the small, cyclic inositol framework, crystallographic information of simple phytate salts has been elusive. This report represents a combined crystallographic, theoretical, and solution binding investigation of a supramolecular macrocyclic complex of phytate. Together, the results provide significant insight to phytate's intramolecular and intermolecular interactions at the microenvironment level. The macrocycle-phytate aggregates consist of phytate anionic pairs, each partly sandwiched by two 24-membered, amide/amine-based cationic macrocycles. The phytate ion pairs hold the tetrameric macrocyclic array together by six strong intermolecular hydrogen bonds. Both phytates crystallize in 1a5e phosphate conformations (one axial (P2) and five equatorial phosphates). Solution NMR binding studies in 1 : 1 DMSO-d6  : D2 O indicate 2 : 1 macrocycle:phytate associations, suggesting that the sandwich-like nature of the complex holds together in solution. DFT studies indicate the likely occurrence of dynamic intramolecular interchange of phosphate protons, as well as important roles for the axial (P2) phosphate in both intramolecular and intermolecular hydrogen bonding interactions.

Supramolecular interaction of inositol phosphates with Cu(II): comparative study InsP6-InsP3

myo-inositol phosphates are an important group of biomolecules that are present in all eukaryotic cells. The most abundant member of this family in nature is InsP6 (H12L1), which interacts strongly...

Supramolecular traps for highly phosphorylated inositol sources of phosphorus

Structurally elusive inositol hexakisphosphates have been trapped in host-guest sandwiches between two picolinamide macrocycles that remain intact in solution, aided by hydrogen bonds and electrostatic interactions. This first report of macrocyclic complexes of inositol hexakisphosphates provides structural insight to significant biosources of phosphorus that impact the global phosphorus cycle.