Click Conjugates of Artificial Ribonucleases: Sequence Specific Cleavage with Multiple Turnover

Area of Science:

• Chemical Biology
• Oligonucleotide Chemistry
• Catalysis

Background:

• RNA-cleaving catalysts are crucial for targeted RNA degradation.
• Oligonucleotide conjugates offer specificity in targeting RNA sequences.
• Efficient and metal-ion-independent RNA cleavage is highly desirable.

Purpose of the Study:

• To develop and characterize novel azido-modified RNA cleaving catalysts conjugated to oligonucleotides.
• To investigate the impact of locked nucleic acid (LNA) modifications on conjugate performance.
• To assess the utility of the resulting conjugates for producing analyzable RNA fragments.

Main Methods:

• Synthesis of azido-modified RNA cleaving catalyst 2 conjugated to alkyne-modified oligonucleotides.
• Hybridization studies with complementary RNA strands.
• Kinetic analysis of RNA cleavage under various conditions (pH, temperature, presence of EDTA).
• Incorporation and evaluation of locked nucleic acid (LNA) nucleotides.

Main Results:

• Conjugates demonstrated specific hybridization and efficient RNA cleavage with multiple substrate turnover.
• RNA half-lives were observed in the range of 6-7 hours at pH 8 and 37 °C.
• Incorporation of LNA nucleotides significantly increased substrate affinities and reaction rates (t½ of 3.5 hours, kobs = 0.20 h⁻¹).
• RNA cleavage proceeded efficiently without metal ions, even in the presence of EDTA.

Conclusions:

• Azido-modified RNA cleaving catalysts conjugated to oligonucleotides represent a potent tool for targeted RNA degradation.
• LNA modifications offer a strategy to enhance the efficiency of these catalytic conjugates.
• The metal-ion-independent cleavage and generation of defined fragments make these conjugates suitable for bioanalytical applications.