1-Deazainosine-impact on RNA structure and role in exploring ribozyme catalysis

Area of Science:

• Biochemistry
• Molecular Biology
• RNA Therapeutics

Background:

• Deazapurine nucleobases are valuable tools for studying RNA structure and function.
• Atomic mutagenesis using modified nucleobases can elucidate RNA-catalyzed reaction mechanisms.

Purpose of the Study:

• To synthesize and characterize 1-deazainosine (c¹I) phosphoramidite for RNA incorporation.
• To analyze the thermodynamic stability and structural properties of c¹I-containing RNA duplexes.
• To investigate the role of c¹I in probing RNA secondary structures and catalytic mechanisms.

Main Methods:

• Solid-phase RNA synthesis using a novel c¹I phosphoramidite.
• UV-melting experiments for thermodynamic analysis of base-pair stability.
• Nuclear Magnetic Resonance (NMR) spectroscopy to determine base-pairing geometry.
• Atomic mutagenesis of the twister ribozyme.

Main Results:

• c¹I phosphoramidite was successfully synthesized and incorporated into RNA.
• c¹I-C base pairs exhibit lower thermodynamic stability than inosine-cytosine (I-C) pairs.
• NMR data indicate c¹I-C pairs primarily adopt a Watson-Crick-like geometry.
• c¹I incorporation did not disrupt RNA duplex integrity and was used to study viral RNA mimic structures.
• Atomic mutagenesis of the twister ribozyme with c¹I provided evidence for active-site guanine involvement in catalysis.

Conclusions:

• 1-deazainosine (c¹I) can be effectively incorporated into RNA and modulates base-pairing properties.
• c¹I is a valuable tool for atomic mutagenesis to investigate RNA structure, stability, and catalysis.
• The findings provide insights into the behavior of deazapurines in nucleic acids and guide their application in RNA research.