Ab initio study of microsolvated Al3+-aromatic amino acid complexes

Area of Science:

• Computational Chemistry
• Biophysical Chemistry
• Quantum Mechanics

Background:

• Aluminum (Al3+) ions interact with biological molecules like aromatic amino acids.
• Understanding solvation effects is crucial for predicting molecular interactions in biological systems.
• Gas-phase studies may not fully represent behavior in solution.

Purpose of the Study:

• To investigate the microhydration of aluminum (Al3+)-aromatic amino acid complexes.
• To determine the influence of water molecules on the structural and thermochemical properties of these complexes.
• To explore the role of metal cation charge and size in solvation.

Main Methods:

• Utilized Density Functional Theory (DFT) with B3LYP/G03 and Plane-Wave Basis Set/Car-Parrinello Molecular Dynamics (PBE/CPMD) methods.
• Analyzed various binding sites for water molecules.
• Calculated binding affinities, structural changes, and thermochemical properties.

Main Results:

• Water molecule binding affinity and solvation are primarily governed by the charge and size of the Al3+ cation.
• A delicate balance exists between steric hindrance and charge transfer to the metal.
• Microhydration stabilizes structures that are unfavored in the gas phase, without requiring bulk solvent models.

Conclusions:

• Microhydration plays a significant role in the stability and structure of Al3+-aromatic amino acid complexes.
• The findings highlight the importance of considering specific solvation shells in computational studies.
• This work provides insights into metal-ion interactions relevant to biological and chemical processes.