Incorporation of Ruthenium Polypyridyl Complexes Into DNA Oligonucleotides by Copper-Free Click Chemistry.

Area of Science:

• Chemical Biology
• Molecular Biology
• Oligonucleotide Synthesis

Background:

• Standard SELEX (Systematic Evolution of Ligands by Exponential Enrichment) methods struggle with complex DNA modifications.
• There is a need for versatile methods to create naïve libraries with diverse chemical functionalities.

Purpose of the Study:

• To develop a method for preparing DNA libraries functionalized with ruthenium polypyridyl complexes.
• To explore the use of strain-promoted azide-alkyne cycloaddition (SPAAC) for DNA modification.

Main Methods:

• Incorporation of dibenzocyclooctyne (DIBAC) moieties into dsDNA using modified nucleoside triphosphates and primer extension (PEX) or PCR.
• Functionalization of DIBAC-modified dsDNA with azide-bearing ruthenium polypyridyl complexes via SPAAC.
• Conversion of modified dsDNA to ssDNA using magnetoseparation.

Main Results:

• Efficient incorporation of DIBAC handles into dsDNA was achieved.
• SPAAC reactions successfully installed over 10 ruthenium polypyridyl complexes onto the DNA.
• Magnetoseparation provided efficient conversion to modified ssDNA.

Conclusions:

• This method allows for the production of longer oligonucleotides with complex modification patterns.
• The SPAAC-click-SELEX methodology opens new avenues for aptamer discovery with enhanced functionalities.