RNA conformational propensities determine cellular activity

Area of Science:

• Molecular Biology
• Biophysics
• Structural Biology

Background:

• Cellular processes depend on biomolecular interactions forming active complexes.
• Intermolecular contacts mediate these interactions, and their disruption alters cell physiology.
• Biomolecular interactions often require conformational changes, impacting binding affinity and cellular activity.

Purpose of the Study:

• To systematically alter and quantify the conformational propensities of HIV-1 TAR RNA.
• To establish the role of ensemble-based conformational propensities in cellular activity.
• To investigate how conformational states influence binding affinity and HIV-1 Tat-dependent transactivation.

Main Methods:

• Systematic alteration of HIV-1 TAR RNA conformations.
• Quantitative measurement of conformational propensities.
• Assessing binding affinities to the HIV-1 Tat protein's RNA-binding region.
• Measuring HIV-1 Tat-dependent transactivation in cellular models.

Main Results:

• Conformational propensities of HIV-1 TAR RNA were systematically altered and determined.
• These propensities accurately predicted binding affinities between TAR RNA and the Tat protein.
• The study successfully predicted the extent of HIV-1 Tat-dependent transactivation.
• An exceptionally rare and short-lived RNA conformational state was identified as driving a cellular process.

Conclusions:

• Ensemble-based conformational propensities play a critical role in cellular activity.
• Understanding conformational dynamics is essential for modeling biological binding energetics.
• This work provides a quantitative framework for assessing the impact of conformational states on biological function.
• The findings highlight the significance of rare conformational states in biological processes.