Theophylline-specific RNA aptamer (T-aptamer)

The theophylline-specific RNA aptamer is a synthetic, tertiary-structured RNA molecule originally identified in 1994 through the SELEX (Systematic Evolution of Ligands by Exponential Enrichment) process [1, 5]. It is renowned for its exceptional affinity and specificity for theophylline, a methylxanthine drug used to treat respiratory diseases, while exhibiting over 10,000-fold lower affinity for the closely related molecule caffeine [2, 6, 8]. This aptamer serves as a premier model system in RNA biochemistry for studying RNA-ligand interactions, folding landscapes, and the conformational selection mechanism of binding [3, 7]. In synthetic biology, it is widely utilized as a functional domain in artificial riboswitches and aptazymes to regulate gene expression, CRISPR/Cas9 activity, and metabolic pathways in response to theophylline [11, 12, 13]. Although not a natural therapeutic target, it is frequently employed as a benchmark in high-throughput screening and structure-based design efforts to develop small molecules that target complex RNA structures [4, 10]. Its well-characterized structure and binding kinetics make it an essential tool for advancing the field of RNA-targeted drug discovery [2, 9].

Other names

Theophylline aptamerTheophylline-binding RNA aptamerTEP-binding aptamer

The theophylline-specific RNA aptamer binds its ligand through a conformational selection mechanism, where the RNA molecule transitions from a flexible unbound state to a rigid, ligand-bound tertiary structure stabilized by specific hydrogen bonds and base-stacking interactions.