How Nanopore Translocation Experiments Can Measure RNA Unfolding

Area of Science:

• Biophysics
• Nanotechnology
• Molecular Biology

Background:

• Electrokinetic translocation of biomolecules through solid-state nanopores is a label-free technique for studying molecular structure and dynamics.
• Distinguishing transfer RNA (tRNA) species relies on translocation times, ion-current noise, and blockage currents.
• Smaller nanopores necessitate tRNA deformation for translocation, allowing inference of mechanical properties from translocation dynamics.

Purpose of the Study:

• To bridge the understanding of tRNA structural dynamics and nanopore measurements.
• To provide a structural and energetic framework for interpreting experimental data.
• To aid in designing methods for macromolecule identification using nanopores.

Main Methods:

• Application of molecular dynamics simulations.
• Utilizing a simplified "structure-based" energetic model.
• Calculation of the free-energy landscape for distinct tRNA species.

Main Results:

• Simulations implicated transient unfolding of the terminal RNA helix during nanopore translocation.
• Distinct tRNA species exhibit differences in nanopore translocation times and distributions.
• The study provides a framework for interpreting nanopore measurements based on tRNA mechanical properties.

Conclusions:

• Nanopore translocation dynamics are influenced by tRNA structural changes, specifically transient unfolding.
• This research offers a method to infer mechanical properties of individual tRNA molecules.
• The findings can advance label-free macromolecule identification strategies using nanopore technology.