Monovalent cation binding to model systems and the macrocyclic depsipeptide, emodepside.

Area of Science:

• Computational Chemistry
• Molecular Modeling
• Quantum Chemistry

Background:

• Emodepside is a cyclic depsipeptide with potential biological activity.
• Understanding ion binding is crucial for drug design and molecular recognition.
• Potassium ion (K+) plays vital roles in biological systems.

Purpose of the Study:

• To systematically investigate emodepside conformations bound to monovalent potassium (K+) ions.
• To characterize the structural, energetic, and bonding properties of these complexes.
• To elucidate the factors governing K+ ion binding to emodepside.

Main Methods:

• Density Functional Theory (DFT) calculations at the M06-2X/6-31+G(d,p) level.
• Characterization of nine emodepside-K+ conformers as stationary points.
• Natural Bond Orbital (NBO) and Block-Localized Wavefunction (BLW) energy decomposition analyses.
• Implicit solvent model (water, DMSO) simulations.

Main Results:

• Identified nine distinct emodepside-K+ conformers.
• A stable, cavitand-like (CC) structure emerged as the most energetically favorable.
• NBO and BLW analyses quantified bonding and energetic contributions to ion binding.
• Solvent effects on complex stability were evaluated.

Conclusions:

• The cavitand-like conformation is a key binding motif for K+ with emodepside.
• Computational methods provide detailed insights into ion-ligand interactions.
• Understanding these interactions can inform the design of new molecules with specific ion-binding properties.