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. 2017 Feb 10;7:42065. doi: 10.1038/srep42065

Figure 4. Thermal stability of hCyaAm followed by tryptophan fluorescence.

Figure 4

Panel (A) Temperature-induced unfolding of hCyaAm at 50 nM followed by intrinsic fluorescence of tryptophan using the ratio of fluorescence emission intensities at 320 nm and 360 nm (rFI 320/360) as described in Materials and Methods. Panel (B) Effect of ionic strength and the presence of the molecular crowding agent Ficoll 100 g/L on the stability of hCyaAm as a function of calcium concentration (i.e., 0, 0.2, 0.5, 1, 2 and 3 mM calcium); hCyaAm in 20 mM Hepes, 50 mM NaCl (grey circles Inline graphic), hCyaAm in 20 mM Hepes, 150 mM NaCl (buffer A, black circles ⦁) and hCyaAm in 20 mM Hepes, 150 mM NaCl, Ficoll 100 g/L (open circles ⚪). Buffer A contains 20 mM Hepes, 150 mM NaCl, pH 7.4. Error bars: S.D. Three independent preparations of hCyaAm were used for this experiment.