RNA adapts its flexibility to efficiently fold and resist unfolding

Area of Science:

• Biophysics
• Molecular Biology
• Nanotechnology

Background:

• Biopolymer structural interconversions are vital for cellular functions.
• Experimental methods to resolve these dynamic structural changes are limited.
• Understanding RNA folding mechanisms is crucial for deciphering biological processes.

Purpose of the Study:

• To investigate the structural rearrangements of the UUCG stem-loop RNA at the single-molecule level.
• To elucidate the folding pathways and conformational states of ultra-stable RNA.
• To understand how RNA flexibility influences folding dynamics and stability.

Main Methods:

• Utilized a nano-electronic device for single-molecule measurements.
• Achieved microsecond time resolution to capture rapid structural changes.
• Analyzed the complete set of structural rearrangements of the UUCG stem-loop.

Main Results:

• The UUCG stem-loop RNA samples at least four conformations.
• Identified two distinct folding pathways, one previously unobserved.
• Demonstrated adaptive pathway selection by modulating RNA flexibility, enhancing folding speed and stability.

Conclusions:

• RNA can stabilize itself by adaptively changing its flexibility.
• This stabilization paradigm broadens the understanding of stable RNA structures.
• The observed mechanism is likely a general strategy employed by all biopolymers.