FIGURE 6.

Far-UV circular dichroism spectra of Stt7. A, far-UV CD spectrum of purified Stt7 in 0.1 m phosphate buffer (pH 8), 12 mm βME, and 0.1% UDM. The spectrum with pronounced negative peaks at 208 and 222 nm shows that the protein is primarily α-helical. B, temperature dependence of ellipticity of Stt7 and b₆f complex, measured at 222 nm in 0.1 m phosphate buffer (pH 8), 0.1% UDM of isolated Stt7 (a, red), spinach b₆f complex (b, blue), and Stt7 together with the b₆f complex (c, purple). d, thermally induced melting function of Stt7 in the presence of b₆f (black), determined by the difference between functions c and b.