In autumn 2023, the Bio-imaging facility of the PIBBS platform has obtained a R&D grant from Biocampus (www.biocampus.cnrs.fr) in a tight collaboration with Chérine Béchara, researcher at the Institut de Génomique Fonctionnelle (Granier-Mouillac team), to develop a FCS approach based on 3 fluorophores grafted on unnatural amino acids. This pilot project aims at establishing 3-color single molecule FRET measurements on a microscope of the PIBBS Optical microscopy facility. It will be used to monitor the correlation of conformational changes associated with the formation of S. aureus leukotoxin octameric pore.