A Peptide Nucleic Acid (PNA) Heteroduplex Probe Containing an Inosine–Cytosine Base Pair Discriminates a Single‐Nucleotide Difference in RNA

Selective discrimination of a single-nucleotide difference in single-stranded DNA or RNA remains a challenge with conventional DNA or RNA probes. A peptide nucleic acid (PNA)-derived probe, in which PNA forms a pseudocomplementary heteroduplex with inosine-containing DNA or RNA, effectively discriminates a single-nucleotide difference in a closely related group of sequences of single-stranded DNA and/or RNA. The pseudocomplementary PNA heteroduplex is easily converted to a fluorescent probe that distinctively detects a member of highly homologous let-7 microRNAs.