Kinetic and Mechanistic Characterization of RSpFAST, a Non-Covalent Versatile Chemogenetic Platform for Fluorescence Imaging
Year: 2026
Type: article
Abstract: Reversibly photoswitchable fluorophores have enabled a broad range of applications in advanced fluorescence bioimaging. Here, we introduce RSpFAST, a new class of reversibly photoswitchable fluorescent labels that combine a biomolecular host (pFAST protein tag) with a reversibly photoisomerizable guest (fluorogen), allowing fluorescence brightness to be modulated through illumination and molecular complexation. We combine thermokinetic, photochemical, and structural investigations to obtain a comprehensive mechanistic and kinetic understanding of RSpFAST. Building on this theoretical framework, we demonstrate in both live and fixed cells that RSpFAST exhibits an unprecedented dual behavior: a stable and wash-free fluorescent labeling tag turns into a negative reversible photoswitcher by decreasing the fluorogen concentration and increasing light intensity. In this photoejection-driven kinetic regime, RSpFAST is shown to be an efficient marker for dynamic contrast and super-resolution microscopy.
DOI: 10.1021/jacs.6c08277
Authors: Yuriy Shpinov, Mrinal Mandal, Vincent van Deuren, Alienor Lahlou, Matthias Le Bec, Raja Chouket, Chaima Hadj Moussa, Clara Bonin, Hessam Sepasi Tehrani, Ian Coghill, Lina El Hajji, Karim Ounoughi, Jaime Franco Pinto, Marie-Aude Plamont, Philippe Pelupessy, Isabel Ayala, Franck Perez, Isabelle Aujard, Thomas Le Saux, Arnaud Gautier, Peter Dedecker, Bernhard Brutscher, Ludovic Jullien
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7204845612