Sensing Metal Ions with Phosphorothioate-Modified DNAzymes.

Area of Science:

• Biochemistry
• Chemical Biology
• Bioanalytical Chemistry

Background:

• Phosphorothioate (PS) modification involves substituting a non-bridging oxygen with sulfur in nucleic acids, enabling novel chemical properties.
• PS modifications are crucial in ribozyme and DNAzyme research for understanding metal binding, bioanalysis, and DNA modification.
• The introduction of PS modifications creates chiral phosphorus centers, necessitating the separation of R_p and S_p diastereomers.

Purpose of the Study:

• To describe methods for separating R_p and S_p diastereomers of phosphorothioate-modified DNA.
• To demonstrate the generation of long, fluorescently modified DNAzyme substrates using HPLC separation and ligation.
• To illustrate the application of these modified substrates in activity assays for metal binding and metal ion detection.

Main Methods:

• Solid-phase DNA synthesis for introducing PS modifications.
• High-Performance Liquid Chromatography (HPLC) for separating R_p and S_p diastereomers.
• Ligation techniques to create long, fluorescently labeled DNAzyme substrates.

Main Results:

• Successful separation of R_p and S_p diastereomers of PS-modified DNA.
• Generation of functional, long DNAzyme substrates with fluorescent labels.
• Demonstration of the utility of modified substrates in metal binding studies and metal ion detection assays.

Conclusions:

• Effective methods for PS diastereomer separation and DNAzyme substrate synthesis were established.
• The developed fluorescently modified DNAzyme substrates are valuable tools for studying metal interactions.
• This approach advances bioanalytical applications and the chemical biology of DNA modifications.