Related Experiment Video
Updated: Jun 13, 2026
Extraction and Quantification of Soluble, Radiolabeled Inositol Polyphosphates from Different Plant Species using SAX-HPLC
Published on: June 26, 2020
Molecular recognition of inositol 1,4,5-trisphosphate and model compounds in aqueous solution by ditopic Zn(2+)
Masanori Kitamura1, Hiroyuki Nishimoto, Keita Aoki
1Faculty of Pharmaceutical Sciences, Tokyo University of Science,2641 Yamazaki, Noda 278-8510, Japan.
Abstract:
We report on molecular recognition of inositol 1,4,5-trisphosphate (Ins(1,4,5)P(3)), an important intracellular second messenger, and some related model compounds, cyclohexanediol bisphosphate derivatives (CDP(2)), by ditopic Zn(2+) complexes containing chiral linkers ((S,S)- and (R,R)-11) in aqueous solution at physiological pH. A crystal structure analysis of (S,S)-11 indicated that the distance between two Zn(2+) ions (6.8 A) is suitable for accommodating two phosphate groups at the 4- and 5-positions of Ins(1,4,5)P(3) and two phosphate groups of trans-1,2-CDP(2). (1)H NMR, (31)P NMR, potentiometric pH, and isothermal calorimetric titration data indicate that (S,S)-11 forms 1:1 complexes with (S,S)- and (R,R)-1,2-CDP(2) at pH 7.4 and 25 degrees C. The apparent 1:1 complexation constants (log K(app)) for (S,S)-11-(S,S)-1,2-CDP(2) and (S,S)-11-(R,R)-1,2-CDP(2) (K(app) = [(S,S)-11-1,2-CDP(2) complex]/[(S,S)-11][1,2-CDP(2)] (M(-1))) were determined to be 7.6 +/- 0.1 and 7.3 +/- 0.1, respectively, demonstrating that both enantiomers of 11 bind to chiral trans-1,2-CDP(2) to almost the same extent. The log K(app) value of 6.3 was obtained for a 1:1 complex of (S,S)-11 with cis-1,3-CDP(2), while a small amount of 2:1 (S,S)-11-cis-1,3-CDP(2) was detected, as evidenced by electrospray ionization mass spectrometry (ESI-MS). In contrast, 11 formed several complexes with trans-1,4-CDP(2). On the basis of isothermal titration calorimetry data for (S,S)- and (R,R)-11 with Ins(1,4,5)P(3), it was concluded that 11 forms a 2:1 complex with Ins(1,4,5)P(3), in which the first molecule of 11 binds to the 4- and 5-phosphates of Ins(1,4,5)P(3) and the second molecule of 11 binds to the 1- and 5-phosphates.
More Related Videos
Related Concept Videos
02:52Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
02:34Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
02:25Molecules with Multiple Chiral Centers
02:05Prochirality
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...