Olha Tkach and members of the Biophotonics of Molecular and Cellular Interactions team led by Yves Mély, , in collaboration with the Instituto de Química Física Blas Cabrera (IQF-CSIC) de Madrid, the Consiglio Nazionale delle Ricerche - Istituto Biostrutture e Bioimmagini, the Department of Chemistry and Biochemistry- University of California and the Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS) studied the potential of an innovative fluorescent analogue of guanosine.
This article published in Physical Chemistry Chemical Physics (PCCP) explores the photochemical properties of isothiazologuanosine (tzG).
The objective? To better understand and utilize this fluorescent probe, which is capable of mimicking the structure and properties of guanosine, while providing a unique window of observation on DNA and RNA.
What they discovered
- Precise monitoring over large time scales and pH ranges: using ultrafast techniques (from femtoseconds to nanoseconds) and quantum calculations, they mapped the proton transfer reactions of tzG between pH –0.6 and 12.
- Unique mechanisms at acidic pH: the molecule rapidly changes its protonation in the excited state, revealing a marked difference between the acid-base properties of the ground state and those of the excited state.
- High pH sensitivity: depending on whether it is protonated or deprotonated, tzG exhibits distinct spectra, fluorescence lifetimes, and quantum yields, making it particularly responsive to environmental changes.
Why is this important?
These results open the way for the use of tzG as a powerful probe for studying nucleic acids and their interactions with proteins. In particular, its ability to respond to local changes in acidity or electrostatic charges could lead to a better understanding of:
- the folding mechanisms of RNA and DNA,
- interactions with proteins,
- and biomolecular dynamics essential to life.
Congratulations to all the authors!
Exploring excited-state proton transfer reactions in isothiazologuanosine, an isofunctional fluorescent analogue of guanosine. Olha Tkach, Lara Martinez-Fernandez, Atzin Esmeralda Ruiz-Lera, Nicolas Humbert, Ludovic Richert, Dmytro Dziuba, Elisa Bombarda, Aurélie Bourderioux, Fabien Hanser, Pascal Didier, Yitzhak Tor, Roberto Improta, Jérémie Léonard and Yves Mély
