Figure 1

In vitro properties of the purified YTnC indicator. (a) A scheme of the original library for optimization of linkers in YTnC indicator and crystal structure of NTnC*2Ca²⁺ complex (pdb 5MWC) for the sensor having a similar design. (b) Absorbance spectra for YTnC in Ca²⁺-free and Ca²⁺-bound states at different pH values. (c) Excitation and emission spectra for YTnC in Ca²⁺-free and Ca²⁺-bound states. (d) Fluorescence intensity for YTnC in Ca²⁺-free and Ca²⁺-bound states as a function of pH. (e) Ca²⁺ titration curves for YTnC in the absence and presence of 1 mM MgCl₂. (f) Maturation curves for YTnC in Ca²⁺-saturated state and mEGFP. (g) Photobleaching curves for YTnC in Ca²⁺-free state and mEGFP. The power of light before objective lens was 7.3 mW/cm². (h) Fast protein liquid chromatography of YTnC (14 mg/ml) in 40 mM Tris-HCl (pH 7.5) and 200 mM NaCl buffer supplemented with 5 mM CaCl₂. Error bars represent the standard deviation for the average of three records.