Skip to main content
. 2021 Apr 29;16(5):891–904. doi: 10.1021/acschembio.1c00100

Figure 1.

Figure 1

In vitro characterization of CTPEs. (a) Working principle of CTPEs: RamR (green) and LmrR (magenta). (b) Fluorescence emission spectra depicting fold change in fluorescence emission intensity of Bodipy495 upon addition of CTPEs. (c) Absorption spectra depicting fold change in the absorption of Bodipy495 after the addition of CTPEs. (d–f) Fold change in Bodipy495 fluorescence emission intensity across pH (d), NaCl concentration (e), and temperature (f) using 5 μM protein and 0.5 μM Bodipy495 in 20 mM Na-MOPS, 150 mM NaCl buffered at pH 7.0. The dotted line in panel f indicates the onset of precipitation of RamR. The solid lines in panels d–f are spline fits, and the color-shaded regions represent SD over three independent measurements. (g) Correlation plots of fold-change in absorbance and fluorescence for 7 fluorogenic dyes. Gray dotted lines connect the values for the respective dye. (h, i) Effect of oxygen on the fluorogenicity of dyes in the presence of CTPEs; panel h, RamR; panel i, LmrR. The fold change in fluorescence in the absence of oxygen (faded points) is comparable to that in the presence of oxygen (solid points). Fold-change in fluorescence of Bodipy625 in the absence of oxygen (indicated with asterisks) could not be measured due to the lack of the appropriate excitation source.