CPMD simulation of Cu2+ -- phenylalanine complex under micro-solvated environment

TL;DR

This study uses CPMD simulations and DFT calculations to explore the structure and solvation of phenylalanine-copper(II) complexes, revealing coordination limits and structural motifs crucial for stability.

Contribution

It provides new insights into the micro-solvation and coordination behavior of Cu2+ with phenylalanine, highlighting structural motifs and solvation limits.

Findings

Maximum Cu2+ coordination number is four.

Phenylalanine is neutral in isolated and mono-hydrated complexes, zwitterionic in others.

A unique structural motif stabilizes the lowest energy complexes.

Abstract

The study combines DFT calculations and CPMD simulations to investigate the structures of phenylalanine-copper (II) ([Phe-Cu]2+) complexes and the micro-solvation processes. ....It is found that the phenylalanine moiety appears to be in the neutral form in isolated and mono-hydrated complexes, but in the zwitterionic form in other hydrated complexes (with n no less than 2). .... The present CPMD simulations reveal that the maximum coordination of Cu2+ in the presence of the Phe ligand does not exceed four: the oxygen atoms from three water molecules and one carboxyl oxygen atom of Phe. Any excess water molecules will migrate to the second solvation shell. Moreover a unique structural motif is present in the lowest energy complexes, which is recognized to be significant in stabilizing the structures of the complexes. .....