Effect of ATP on the structure/conformation of M. leprae HSP18.
(A) Intrinsic tryptophan fluorescence spectra of HSP18 (0.05 mg/ml) in absence and presence of 1 mM ATP were recorded in the range 310–400 nm at 25°C. The excitation wavelength was 295 nm. Excitation and emission slit widths were 5 nm each. Data were recorded at a wavelength resolution of 0.5 nm. (B) Far-UV CD spectra of HSP18 in absence and presence of 1 mM ATP. Spectra were recorded for 0.2 mg/ml protein (in 10 mM phosphate buffer, pH 7.5) using a cell of 1 mm path length. The data interval was 1 nm. (C) Intensity particle size distribution spectra of M. leprae HSP18 were recorded at 25°C temperature in presence or absence of 1 mM ATP. Each of these spectra is an average of 48 scans.