SLIM (Shortened Lifetime Imaging Marker) is a highly photostable green fluorescent protein with fluorescence lifetime shortened/reduced relative to the common GFPs (1300 ps vs 2.5-3 ns) [Mamontova et al., 2018]. SLIM carries glycine-tyrosine-glycine (GYG) chromophore and demonstrates fast chromophore maturation under physiological conditions. It also shows weak reactivity in excited-state redox-chemistry and thus – low phototoxicity.

For multiparameter FLIM in green channel SLIM can be used with fluorescent proteins with similar fluorescence spectra and different fluorescence lifetimes: BrUSLEE (800 ps), SLIM (1.3 ns), TagGFP2 (3.2 ns).