Fig. 1: In vitro dependence of the sensor fluorescence on light illumination and Ca2+ levels. | Nature Communications

Fig. 1: In vitro dependence of the sensor fluorescence on light illumination and Ca2+ levels.

From: Absolute measurement of cellular activities using photochromic single-fluorophore biosensors and intermittent quantification

Fig. 1

a, b Cyan- and violet-light-induced photochromism in purified proteins in the presence (a) and absence (b) of free Ca2+. The cyan and violet bars at the bottom of the plots show the sequence of the illumination. F0 and Fend refer to the intensities that would be used to calculate the \({({{\Delta }}{{{{F}}}}/{{{{{F}}}}}_{0})}_{{{{{{{{\rm{hv}}}}}}}}}\) values. c Difference in the observed fluorescence between Ca2+-saturated (sat) and Ca2+-free conditions (apo), normalized by the fluorescence of the sat-form, as measured in bacterial cell lysates. d Photochromism contrast \({({{\Delta }}{{{{F}}}}/{{{{{F}}}}}_{0})}_{{{{{{{{\rm{hv}}}}}}}}}\) as a function of \(\left[{{{{{{{{\rm{Ca}}}}}}}}}^{2+}\right]\).

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