Far UV CD spectra of, apoS100A13 (Panel-A, curve-a) and apoS100A13 in the presence of pS (Panel-A, curve-b) and holoS100A13 in the presence of pS (Panel-B, curve-b, and 2 mM Ca2+ (Panel-B, curve-a). The concentration of S100A13 used was 100 uM. Far UV CD spectra were acquired at pS to S100A13 ratio of 10 to 1. All samples were prepared in 10 mM tris (pH 7.5) containing 100 mM NaCl at 25 °C. The spectra are an average of 5 scans. Necessary background corrections were made in all spectra.