Unveiling a novel RNA G-triplex structure: its function and potential in CRISPR-based diagnostics†

Abstract

We report the discovery of a novel higher-order RNA structure, RNA G-triplex (rG3), formed by the TERRA sequence. Through CD spectroscopy, NMR analysis, and molecular modeling, we confirmed its stable, parallel conformation. rG3 exhibits strong binding to thioflavin T (ThT), N-methyl mesoporphyrin IX (NMM), and hemin, showcasing its potential as a biosensing element. Additionally, CRISPR-Cas13a trans-cleaves rG3, demonstrating its utility as a sensitive reporter in diagnostic applications. These findings expand the structural diversity of RNA and suggest new avenues for RNA-based biosensors and CRISPR diagnostics.