Studying DNA G-Quadruplex Aptamer by ¹⁹F NMR

Area of Science:

• Biophysical Chemistry
• Nucleic Acid Chemistry
• Spectroscopy

Background:

• G-quadruplexes are crucial nucleic acid structures with therapeutic potential.
• Thrombin-binding aptamer (TBA) is a well-established model for G-quadruplex studies.
• Understanding G-quadruplex dynamics and interactions is key to aptamer development.

Purpose of the Study:

• To investigate the utility of fluorine-19 Nuclear Magnetic Resonance (¹⁹F NMR) for studying TBA DNA G-quadruplexes.
• To systematically analyze the structural features of ¹⁹F-labeled TBA G-quadruplexes.
• To demonstrate ¹⁹F NMR's capability in observing G-quadruplex structural transitions and thrombin binding.

Main Methods:

• Systematic labeling of all thymidine positions in the TBA G-quadruplex aptamer with fluorine-19 (¹⁹F).
• Utilizing ¹⁹F NMR spectroscopy to monitor structural conformations.
• Applying ¹⁹F NMR to determine thermodynamic parameters.
• Observing the complex formation between the TBA G-quadruplex and thrombin using ¹⁹F NMR.

Main Results:

• ¹⁹F NMR successfully detected structural changes between the G-quadruplex and single-stranded forms of the TBA aptamer.
• Thermodynamic parameters of the DNA G-quadruplex aptamers were determined using ¹⁹F NMR signals.
• The formation of the TBA G-quadruplex-thrombin complex was successfully observed via ¹⁹F NMR.

Conclusions:

• ¹⁹F NMR is a powerful and versatile technique for characterizing the structure and dynamics of aptamer G-quadruplexes.
• ¹⁹F NMR provides valuable insights into G-quadruplex conformational transitions.
• This spectroscopic approach facilitates the study of aptamer-protein interactions, such as TBA with thrombin.