Visible-Light-Controlled Formation of G-Quadruplexes

Area of Science:

• Supramolecular chemistry
• Chemical biology
• Photochemistry

Background:

• Guanine (G)-quadruplexes are stable structures formed by G-quartets and metal cations.
• Controlling G-quadruplex formation dynamically is crucial for various applications.
• Existing methods for G-quadruplex control often lack external stimuli responsiveness.

Purpose of the Study:

• To develop a method for visible light-controlled G-quadruplex assembly.
• To investigate the direct functionalization of guanosine with photoswitches for G-quadruplex formation.
• To compare the efficiency of different photoswitches in controlling G-quadruplex dynamics.

Main Methods:

• Direct functionalization of guanosine with ortho-substituted azobenzene (osAZO) and arylazopyrazole (AAP) photoswitches.
• Formation of G-octamers using E isomers of photoswitch derivatives.
• Induction of G-quadruplex disassembly using Z isomers of photoswitch derivatives.
• Spectroscopic analysis and theoretical calculations to evaluate switching efficiency.

Main Results:

• Visible light can control G-quadruplex formation and disassembly through direct guanine modification.
• E isomers of osAZO and AAP derivatives promote G-quadruplex assembly into D4-symmetric G-octamers.
• Z isomers of these photoswitches induce G-quadruplex disassembly.
• The AAP derivative demonstrated near-quantitative reversible control over G-quadruplex formation.

Conclusions:

• This study presents the first visible-light-controlled G-quadruplex assembly achieved by direct guanine modification.
• Photoswitchable guanosine derivatives offer a novel platform for dynamic control of G-quadruplex structures.
• The findings open new avenues for light-responsive biomaterials and molecular devices.