Fig. 4.

POPS facilitates the association of moesin-FERM with TMR-CLS reconstituted in the phospholipid liposome. TMR-CLS/POPC/POPS liposomes, at the pep-tide-to-lipid molar ratio of 1:1000, were prepared and diluted in 50 mM Tris and 150 mM NaCl (pH 7.4) to the final TMR-CLS concentration of 5 nM. Moesin-FERM dissolved in the same buffer containing 5 nM TMR-CLS/POPC/POPS was titrated to the TMR-CLS/POPC/POPS liposome. (a) TMR fluorescence emission spectra of TMR-CLS reconstituted in liposomes of various POPC/POPS composition. Each spectrum is denoted by the percentage of POPS in the liposome. The emission spectra were recorded for 555–650 nm with the excitation wavelength at 542 nm. Each spectrum was the average of three scans and corrected for background signals from the buffer and the empty liposome. (b) TMR fluorescence emission spectra of the same TMR-CLS liposome samples after the addition of 10% SDS to dissolve the liposome. (c) Binding of moesin-FERM to TMR-CLS reconstituted in liposomes of various POPC/POPS composition, monitored by the change in TMR fluorescence at 575 nm. The lines are fitted binding curves to each titration.