Fig. 3: Reversible gating by LGC.

a Scheme showing LGC, containing donor dye on the plate (green) and acceptor dye on the lid (red). The addition of key and reverse key leads to respectively, opening and closing of the lid—resulting in closing or increasing the distance between the two dyes. b Representative fluorescence spectra for one full cycle of lid opening-closing (D and A on the graph represent fluorescence maxima for donor and acceptor respectively) and c FRET efficiency corresponding to reversible gating of LGC lid over four full cycles; data points and error bars respectively represent average relative FRET efficiency and standard deviation of the mean from n = 3 technical repeats. Initially, when the lid is closed, the spatial proximity of the donor and acceptor enables FRET, resulting in lower donor fluorescence, higher acceptor fluorescence (b, solid pink), and high FRET efficiency (c, close, pink dots). Opening the lid using a key (dynamic-open) moves the donor and acceptors far from each other. Thus, FRET ceases, resulting in higher donor fluorescence, lower acceptor fluorescence (b, solid blue) and lower FRET efficiency (c, open, blue dots). Closing the lid back from its open state using a reverse key (dynamic-closed) restores FRET, again resulting in lower donor fluorescence, higher acceptor fluorescence (b, dashed pink), and high FRET efficiency (c, closed, pink dots). Source data are provided as a Source Data file.