Reversible energy-transfer switching on a DNA scaffold.

Area of Science:

• Molecular Biology
• Photochemistry
• Biophysics

Background:

• Förster Resonance Energy Transfer (FRET) is a distance-dependent physical process.
• Photochromic molecules can change color or conformation upon light exposure.
• Controlling molecular interactions with light is crucial for advanced applications.

Purpose of the Study:

• To investigate the reversible photochromic control of FRET between dyes on a DNA scaffold.
• To utilize spiropyran isomerization for modulating FRET efficiency.

Main Methods:

• Covalent attachment of Pacific Blue (PB) and Alexa488 (A488) dyes to a DNA scaffold.
• Incorporation of a spiropyran derivative for photochromic switching.
• Monitoring FRET efficiency changes under UV and visible light irradiation.

Main Results:

• FRET between PB and A488 was observed when spiropyran was in its closed spiro form.
• UV-induced isomerization of spiropyran to the open merocyanine form effectively quenched FRET.
• Visible light exposure reversed the process, restoring FRET by inducing spiropyran re-isomerization.

Conclusions:

• Spiropyran photochromism provides a reversible mechanism to control FRET on a DNA scaffold.
• This light-switchable FRET system has potential applications in molecular sensing and logic gates.