Figure 3.

Existence and subsequent melting of ordered domains in an otherwise fluid lipid matrix. Headgroup-dependent formation of sterol-containing ordered domains was studied using fluorescence quenching of the cholesterol analog CTL by the quencher 7SLPC (left panels). The anisotropy of tPa (right panels) was further used to study the melting of ordered domains, not necessarily containing sterol. The color scheme depicts the size of the headgroup according to Me₃ (black), Me₂ (red), Me₁ (green), and Me (blue) for SM analogs (upper panels) and PC analogs (lower panels). Samples consisted of POPC/headgroup analog/cholesterol (60:30:10, molar ratio), and in the CTL quenching study, 7SLPC replaced 50 mol % of POPC in the fluid matrix of the F-sample.