Backbone-base interactions critical to quantum stabilization of transfer RNA anticodon structure

Area of Science:

• Molecular Biology
• Biophysics
• Computational Chemistry

Background:

• Transfer RNA (tRNA) anticodons exhibit a highly ordered 3'-stacked conformation.
• Understanding the forces stabilizing this structure is crucial for RNA function.

Purpose of the Study:

• To computationally investigate the intramolecular interactions stabilizing the tRNA anticodon stair-stepped conformation.
• To elucidate the relative contributions of base stacking versus backbone-base interactions.

Main Methods:

• Utilized Density Functional Theory (DFT) at the M06-2X/6-31+G(d,p) level.
• Employed Natural Bond Orbital (NBO) analysis for intramolecular interaction calculations.
• Analyzed ten X-ray crystal structures of tRNA anticodons from the Protein Data Bank (PDB).

Main Results:

• Electrostatic interactions between the sugar-phosphate backbone and bases were identified as the primary stabilizing force.
• Interbase stacking interactions were found to be weak and inconsistent.
• Aqueous solvation had a minimal impact on the observed intramolecular interactions.

Conclusions:

• The tRNA anticodon structure is predominantly stabilized by backbone-base electrostatic interactions.
• Traditional models emphasizing base stacking may need revision for tRNA anticodons.
• Computational methods provide key insights into RNA structural dynamics.