An ion-controlled four-color fluorescent telomeric switch on DNA origami structures

Area of Science:

• Nanotechnology
• Biochemistry
• Molecular Biology

Background:

• Guanine (G) quadruplex formation in telomeric DNA is crucial for cellular processes and drug targeting.
• DNA origami nanostructures enable precise control over DNA folding and ion selectivity.
• Potassium ion (K(+)) selectivity in G-quadruplex formation is essential for specific biological sensing.

Purpose of the Study:

• To demonstrate the reversible switching of G-quadruplex structures on DNA origami.
• To characterize the K(+)-selective G-quadruplex formation and its reversal using a cryptand.
• To integrate the G-quadruplex switch into photonic networks for FRET-based applications.

Main Methods:

• Utilizing DNA origami nanostructures to immobilize telomeric DNA.
• Employing Förster resonance energy transfer (FRET) with fluorescein (FAM) and cyanine3 (Cy3) dyes for structural monitoring.
• Using a cryptand to induce and reverse K(+)-mediated G-quadruplex formation.

Main Results:

• Achieved highly K(+)-selective G-quadruplex formation on DNA origami, even with high sodium ion (Na(+)) concentrations.
• Demonstrated reversible switching between single-stranded DNA and G-quadruplex states.
• Successfully integrated the G-quadruplex switch into three- and four-color FRET cascades, showcasing its function as a switchable transmitter.

Conclusions:

• The K(+)-selective G-quadruplex switch on DNA origami is reversible and highly specific.
• This system offers a novel platform for developing advanced biosensors and photonic devices.
• The integration into FRET cascades highlights the potential for complex molecular logic and signal processing.