Figure 2.

Key physical characteristics for quantifying curvature sensitivity of single cardiolipin molecules. (A) Cardiolipin's unique dimeric structure, with two phosphatidyl head groups and four acyl chains, is indicative of a conical shape with a small radius of curvature R_lipid and hence a preference for highly curved geometries. (B) The energy scale κ is set by the stiffness of the membrane for bending. (C) The enhanced curvature of the pole is the difference between the curvature at the pole and at the cylindrical midcell, ΔC_cell = 1/R. The combination of κ, C_lipid,, ΔC_cell, and the surface area A_lipid then determines the extent to which the molecule will preferentially localize at the pole.