FIGURE 5.

CD spectra of various c-type apocytochromes and their interacting partners, CcmI and CcmI-2, in the absence of hemin. A, far-UV CD spectra between 195 and 240 nm of various c-type apocytochromes (15 μm) were recorded in the absence of hemin. Apocytochromes c₂ and c′ exhibited CD spectra typical of disordered coils, whereas apocytochrome c₁ and its truncated derivative, apocytochrome c₁t39, showed characteristics of typical α-helical proteins. B, far-UV CD spectra between 195 and 240 nm of His₁₀-CcmI and His₁₀-CcmI-2 (1.5 μm) in the absence of hemin indicated their high α-helical contents. Both apocytochrome c₁t39 and CcmI-2 are one helix shorter than apocytochrome c₁ and CcmI, respectively, and the amplitudes of their ellipticity are comparatively lower.