Cleaving Folded RNA with DNAzyme Agents

• Published in: Chembiochem : a European journal of chemical biology 2024-01, Vol.25 (1), p.e202300637-n/a
• Main Authors: Nedorezova, Daria D., Dubovichenko, Mikhail V., Kalnin, Arseniy J., Nour, Moustapha A. Y., Eldeeb, Ahmed A., Ashmarova, Anna I., Kurbanov, Gabdulla F., Kolpashchikov, Dmitry M.
• Format: Article
• Language: English
• Subjects: Affinity; affinity/specificity dilemma; Algorithms; Binding; binding folded RNA; Cleavage; Deoxyribozymes; DNA, Catalytic - metabolism; DNAzymes kinetics; Folding; Gene therapy; Magnesium; mRNA; Oligonucleotides; Pharmacology; Product inhibition; Ribonucleic acid; RNA; RNA - chemistry; RNA, Messenger; selectivity of RNA recognition; Substrates; Workflow
• ISSN: 1439-4227; 1439-7633
• DOI: 10.1002/cbic.202300637

Cleavage of biological mRNA by DNAzymes (Dz) has been proposed as a variation of oligonucleotide gene therapy (OGT). The design of Dz‐based OGT agents includes computational prediction of two RNA‐binding arms with low affinity (melting temperatures (Tm) close to the reaction temperature of 37 °C) to avoid product inhibition and maintain high specificity. However, RNA cleavage might be limited by the RNA binding step especially if the RNA is folded in secondary structures. This calls for the need for two high‐affinity RNA‐binding arms. In this study, we optimized 10–23 Dz‐based OGT agents for cleavage of three RNA targets with different folding energies under multiple turnover conditions in 2 mM Mg2+ at 37 °C. Unexpectedly, one optimized Dz had each RNA‐binding arm with a Tm ≥60 °C, without suffering from product inhibition or low selectivity. This phenomenon was explained by the folding of the RNA cleavage products into stable secondary structures. This result suggests that Dz with long (high affinity) RNA‐binding arms should not be excluded from the candidate pool for OGT agents. Rather, analysis of the cleavage products’ folding should be included in Dz selection algorithms. The Dz optimization workflow should include testing with folded rather than linear RNA substrates. DNAzymes (Dz) 10–23 were optimized to cleave three RNA targets having different folding energies. The optimized Dzs can have RNA‐binding arms with a melting temperature much higher than the reaction temperature. The article discusses this phenomenon and suggests changes in the Dz optimization workflow to achieve optimal Dz catalytic activity in vivo.