FIGURE 3.

Micelle-vesicle transition of C₁₂E₁₀/DLPC and C₁₂E₁₀/DMPC mixtures. A, 90° light scattering (470 nm) expressed in arbitrary units (a.u.) as a function of X_PC for C₁₂E₁₀/DLPC (white circles) and C₁₂E₁₀/DMPC (black circles) mixtures in the same conditions in which the Ca²⁺-ATPase activity was determined in Fig. 1A. No enzyme was added in the mixture. Inset, 90° light scattering (470 nm) as a function of C₁₂E₁₀ concentration (in the absence of DMPC or DLPC). B, hydrodynamic radius (R_H) of the micelles/vesicles as a function of X_DLPC (white circles) and X_DMPC (black circles), in the same conditions in which the Ca²⁺-ATPase activity was determined in Fig. 1A. No enzyme was added in the mixture. Inset, normalized experimental autocorrelation curve obtained at X_DMPC = 0.25. By fitting a three-dimensional diffusion model (Equation 2) to these experimental data, we obtained a characteristic residence time (τ_D) of the particles diffusing through the observation volume. The residence time can be related to the diffusion coefficient D (Equation 3) and finally with the R_H (Equation 4) of the fluorescent particles. The values shown are the mean ± S.E. (error bars) of at least three independent experiments performed in triplicate.