The first solvation shell of aluminum (III) and magnesium (II) cations in a protein model environment

Abstract

AbstractAluminum (III) cation interactions with relevant bioligands have been studied in a protein‐model environment (in the gas and aqueous phases) using density functional theory methods. The protein model consists of the metal cation bound to a chosen bioligand and water molecules interacting with the cation to complete its first coordination shell. The ligands are the functional groups of the amino acid side chains. Binding energies and formation energies are calculated in both phases. Analogous magnesium (II) complexes are also calculated, and the possibility of magnesium/ aluminum exchange is estimated. The effect of the dielectric media is also discussed. This aims to model different regions inside a protein (solvent accessible and buried regions). It is found that the effect of the dielectric is very important, for example, for the negatively charged ligand complexes, magnesium/aluminum exchange is possible only in low dielectric environments such as partially buried protein regions. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004