Fig. 5.

A hypothetical scheme of KcsA tetramer folding in PC (a) or PE (b) containing lipid bilayers. In PC (large headgroup), the tetramer is loosely packed. However, in the presence of PE (small headgroup), the tetramer is squeezed and adopts a more compact structure similar to PA-KcsA complex (PE ≅ PA). The dotted lines represent a hypothetical scale to elaborate tetramer stretching or squeezing pattern in PC or PE ≅ PA lipid bilayers, respectively. The coloring of KcsA tetramer indicates the tetramer packing behavior. The N- and C-termini are not shown