Titration of the wild type (WT) HspB1 and its N-terminal mutants with the environmental probe bis-ANS.

<p>Protein samples (0.1 mg/ml) in buffer FF (50 mM phosphate (pH 7.5) containing 100 mM NaCl and 15 mM β-mercapthoethanol (ME)) were titrated with a stock solution of bis-ANS (360 μM in buffer FF). Fluorescence was measured using excitation wavelength of 385 (slit width 2.5 nm) and an emission wavelength of 495 nm (slit width 5 nm). All measurements were performed at 25°C. The titration curve of the buffer in the absence of any protein is marked as control. The data presented are mean values of six independent measurements with error bars corresponding to standard deviation.