Synergy of Intramolecular Hydrogen-Bonding Network in myo-Inositol 2-Monophosphate: Theoretical Investigations into the Electronic Structure, Proton Transfer, and pKa

This work demonstrates the pivotal role that an intramolecular hydrogen-bonding network (intra-HBN) plays in the determination of the conformation of myo-inositol 2-monophosphate (Ins(2)P1), a member of the inositol phosphate family of compounds, which are important participants in the role that phosphates play in biological and environmental chemistry. For biologically significant compounds that contain phosphate and hydroxyl groups, Ins(2)P1 is a model system for studying both the primary forces that determine their conformations and their chemical properties from the effect of phosphate group addition. We performed ab initio calculations to determine the intra-HBN within important thermally accessible conformations for neutral Ins(2)P1 and its anions, Ins(2)P11- and Ins(2)P12-. The results show that the global minima prefer 1a/5e structures where the phosphate group is in the axial position with all −OH groups in the equatorial positions. The calculations of transition state structures for ring inversi...