Simulation of interactions between nucleic acid bases by refined atom-atom potential functions

Area of Science:

• Structural Biology
• Computational Chemistry
• Biophysics

Background:

• Understanding the forces governing nitrogenous base interactions is fundamental to nucleic acid structure and function.
• Accurate modeling of these interactions requires precise potential energy functions.

Purpose of the Study:

• To calculate the interaction energy between nitrogenous bases as a function of their spatial arrangement.
• To propose refined atom-atom potential functions for modeling base interactions.
• To identify stable configurations of base pairs based on calculated interaction energies.

Main Methods:

• Development and application of refined atom-atom potential functions, including electrostatic, van der Waals (6th or 10th power), and repulsion (12th power) terms.
• Calculation of interaction energies for various relative positions of nitrogenous bases.
• Characterization of the potential energy surface near identified minima.

Main Results:

• Two main groups of energy minima were identified: coplanar arrangements with hydrogen bonding and stacked arrangements.
• 28 distinct energy minima correspond to coplanar base pairs stabilized by two or three hydrogen bonds (e.g., N-H...O, N-H...N).
• Calculated optimal base pair positions closely match experimentally observed configurations in nucleic acids and tRNA.

Conclusions:

• The refined potential functions accurately predict stable nitrogenous base pairing configurations.
• Identified minima provide a detailed energetic map for base interactions, consistent with experimental and quantum-mechanical data.
• These findings enhance our understanding of the structural basis of genetic information storage and transfer.