A New Variant of Emissive RNA Alphabets

• Published in: Chemistry : a European journal 2022-03, Vol.28 (13), p.e202104472-n/a
• Main Authors: Ludford, Paul T., Yang, Shenghua, Bucardo, Marcela S., Tor, Yitzhak
• Format: Article
• Language: English
• Subjects: Adenosine; Adenosine deaminase; Antimetabolites; Chemistry; Coloring Agents; DNA-directed RNA polymerase; Emission; emissive nucleosides; Fluorescence; fluorescent probes; Guanine; Guanine deaminase; Nucleosides; Perturbation; Ribonucleosides; RNA; RNA polymerase; Substrates
• ISSN: 0947-6539; 1521-3765; 1521-3765
• DOI: 10.1002/chem.202104472

A new fluorescent ribonucleoside alphabet (mthN) consisting of pyrimidine and purine analogues, all derived from methylthieno[3,4‐d]pyrimidine as the heterocyclic core, is described. Large bathochromic shifts and high microenvironmental susceptibility of their emission relative to previous alphabets derived from thieno[3,4‐d]pyrimidine (thN) and isothiazole[4,3‐d]pyrimidine (tzN) scaffolds are observed. Subjecting the purine analogues to adenosine deaminase, guanine deaminase and T7 RNA polymerase indicate that, while varying, all but one enzyme tolerate the corresponding mthN/mthNTP substrates. The robust emission quantum yields, high photophysical responsiveness and enzymatic accommodation suggest that the mthN alphabet is a biophysically viable tool and can be used to probe the tolerance of nucleoside/tide‐processing enzymes to structural perturbations of their substrates. The substrate scope of T7 RNA Polymerase and adenosine deaminase (ADA) are expanded by the introduction of a new ribonucleoside alphabet based on a methylthieno[3,4‐d]pyrimidine core. The majority of the new analogues display significantly red shifted emission relative to the corresponding thieno[3,4‐d]pyrimidine and isothiazolo[4,3‐d]pyrimidine based analogues.