Modulation of dynamic aggregation in fluorogenic SNAP-tag probes for long-term super-resolution imaging

The combination of super-resolution microscopy and synthetic fluorescence probes has emerged as a universal tool to monitor dynamic biological events at the nanometer scale.However,the limited site-specificity and fluorogenicity of synthetic fluorescent probes make it still difficult to realize long-term super-resolution imaging.Herein,we introduce a dynamic aggregation mediated SNAP-tag fluorogenic probe,BGAN-Aze,which can specifically bind to various SNAP-tag fusion proteins with 41-fold fluorescence enhancement.The equilibrium between the non-fluorescent aggregate/dimer(A–D)and the fluorescent monomer(M)of BGAN-Aze acts as an effective method to reduce the fluorescence background and endow BGAN-Aze with the capability of conducting washing-free super-resolution imaging of various intracellular and extracellular proteins.Using this probe,we monitored multiple dynamic biological events,such as MMC,mitophagy,the fusion of nucleolus,and the growth and contact of filopodia.We expect that BGAN-Aze will become a widely used SNAP-tag for super-resolution imaging of dynamic biological events and the A-D-M equilibrium can be a general strategy for designing fluorogenic probes.