Specific Interaction between a Fluoroquinolone Derivative, KG022, and RNAs with a Single Bulge

Area of Science:

• Medicinal Chemistry
• Molecular Biology
• Drug Discovery

Background:

• Small molecules targeting RNA represent a promising therapeutic strategy.
• Fluoroquinolone derivatives are being explored for their RNA-binding capabilities.

Purpose of the Study:

• To investigate the influence of adjacent base pairs on the interaction between fluoroquinolone derivative KG022 and RNA.
• To elucidate the structural basis for KG022's RNA binding affinity.

Main Methods:

• Proton Nuclear Magnetic Resonance (¹H NMR) spectroscopy to analyze RNA-KG022 interactions.
• Fluorine-19 Nuclear Magnetic Resonance (¹⁹F NMR) spectroscopy to confirm binding.
• Temperature-dependent NMR studies to assess complex stability.

Main Results:

• KG022 binds to RNAs with single-bulged G or C residues and specific 3' adjacent base pairs (GC or AU).
• KG022 shows a preference for UA and CG base pairs at the 5' position adjacent to the bulge.
• Stable complex formation is attributed to stacking interactions between the fluoroquinolone ring and purine bases.
• More stable complexes were observed with CG base pairs compared to UA base pairs at the 5' adjacent position.

Conclusions:

• The study identifies specific RNA sequence contexts that enhance KG022 binding affinity.
• Findings provide valuable insights for designing novel small molecules with improved RNA-targeting capabilities.
• This work contributes to the advancement of RNA-targeted drug discovery.