Stacking and hydrogen bond interactions between adenine and gallic acid

Area of Science:

• Computational Chemistry
• Molecular Interactions
• Biophysics

Background:

• Plant polyphenols like gallic acid and DNA bases such as adenine are crucial biomolecules.
• Understanding their intermolecular interactions, including hydrogen bonds and stacking, is key to their function.
• These interactions influence molecular recognition, stability, and biological activity.

Purpose of the Study:

• To investigate and quantify the relative contributions of hydrogen bonds and stacking interactions in gallic acid and adenine dimers.
• To establish relationships between complex stability, charge transfer, and intermolecular bond properties.
• To elucidate the physical effects of different energy components on dimer stabilization.

Main Methods:

• Density Functional Theory (DFT) calculations were employed to model the dimers.
• DFT-based Symmetry-Adapted Perturbation Theory (DFT-SAPT) was utilized to dissect the interaction energies.
• Analysis focused on hydrogen bonds, non-hydrogen bonds, charge transfer, and dispersion contributions.

Main Results:

• Hydrogen bonds were identified as the predominant stabilizing factor for the studied dimers.
• Increased number and strength of hydrogen bonds correlated with lower dimer energies.
• Stacking interactions contribute to stabilization, particularly in dimers where dispersion forces are significant, as seen in dimer III.

Conclusions:

• Hydrogen bonding is the primary determinant of stability in gallic acid and adenine dimers.
• Stacking interactions provide additional stabilization, with their importance linked to non-hydrogen bonding and dispersion energies.
• The findings offer insights into the molecular recognition and stability of biologically relevant polyphenol-nucleobase systems.