High-throughput dissection of the thermodynamic and conformational properties of a ubiquitous class of RNA tertiary contact motifs.Despite RNA's diverse secondary and tertiary structures and its complex conformational changes, nature utilizes a limited set of structural "motifs"-helices, junctions, and tertiary contact modules-to build diverse functional RNAs.  Here, we adapt RNA-MaP to study the thermodynamic and conformational properties of tetraloop/tetraloop receptor (TL/TLR) tertiary contact motifs, analyzing 1,493 TLR sequences from different classes.  Furthermore, their stability correlated with natural frequency, suggesting thermodynamics as the dominant selection pressure.  In contrast, other TL/TLRs displayed heterogenous conformational behavior and appear to not be under strong thermodynamic selection.  Our results build toward a generalizable model of RNA-folding thermodynamics based on the properties of isolated motifs, and our characterized TL/TLR library can be used to engineer RNAs with predictable thermodynamic and conformational behavior.
THERM