Extended Peptide Nucleic Acid Nucleobases Based on Isoorotic Acid for the Recognition of A–U Base Pairs in Double‐Stranded RNA

Abstract Peptide nucleic acids (PNA) with extended isoorotamide containing nucleobases ( I o ) were designed for binding A–U base pairs in double‐stranded RNA. Isothermal titration calorimetry and UV thermal melting experiments revealed improved affinity for A–U using the Io scaffold in PNA. PNAs having four sequential Io extended nucleobases maintained high binding affinity.