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Theoretical study of the 2:1 Mg 2+ and Ca 2+ complexes of ionophore A23187
Author(s) -
Gresh Nohad,
Pullman Alberte
Publication year - 2009
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560240723
Subject(s) - ionophore , chemistry , solvation , molecule , hydration energy , solvation shell , ion , ligand (biochemistry) , chemical physics , computational chemistry , crystallography , calcium , organic chemistry , receptor , biochemistry
A theoretical study based on the X‐ray coordinates has been performed to compare the stability of the Ca 2+ and Mg 2+ complexes of ionophore A23187. The calculations show that the presence of the water molecule which is observed in the crystal of the Ca 2+ complex as a seventh ligand to the ion is necessary to bring the stability of this complex in the range of that of the Mg 2+ complex. They show further that two other water molecules may be bound to the first one in a second solvation shell of the Ca 2+ complex. The additional stabilization energy brought about by these two molecules stabilizes the Ca 2+ complex with respect to the Mg 2+ complex. Electrostatic properties of the complexes are discussed.