Programmable DNA Interstrand Crosslinking by Alkene-Alkyne [2 + 2] Photocycloaddition

Area of Science:

• Biochemistry
• Molecular Biology
• DNA Nanotechnology

Background:

• Covalent crosslinking of DNA is crucial for various applications.
• Developing efficient and controlled crosslinking methods is an ongoing challenge.

Purpose of the Study:

• To present a novel light-induced interstrand DNA crosslinking reaction.
• To utilize the modified nucleoside 5-phenylethynyl-2'-deoxyuridine (Phe dU) for this purpose.

Main Methods:

• Incorporation of Phe dU into DNA duplexes.
• Induction of crosslinking via short light irradiation.
• Investigation of crosslinking mechanism involving base pairing, metal ions, and hydrophobic stacking.

Main Results:

• Efficient formation of Phe dU dimers through photochemical alkene-alkyne [2 + 2] cycloaddition.
• Crosslinking programmed by base pairing and metal ion interactions.
• Demonstration that crosslinked DNA binds helicase but prevents unwinding.

Conclusions:

• The developed method provides efficient light-induced DNA crosslinking.
• The covalent crosslink created by Phe dU can inhibit DNA unwinding.
• This technique holds promise for applications in biochemistry and structural biology, particularly for studying DNA-protein interactions.