Penetration of phospholipid membranes by poly-l-lysine depends on cholesterol and phospholipid composition

Publication date: Available online 15 November 2019Source: Biochimica et Biophysica Acta (BBA) - BiomembranesAuthor(s): Amy Gorman, Khondker R. Hossain, Flemming Cornelius, Ronald J. ClarkeAbstractClusters of positively-charged basic amino acid residues, particularly lysine, are known to promote the interaction of many peripheral membrane proteins with the cytoplasmic surface of the plasma membrane via electrostatic interactions. In this work, cholesterol's effects on the interaction between lysine residues and membranes have been studied. Using poly-l-lysine (PLL) and vesicles as models to mimic the interaction between lysine-rich protein domains and the plasma membrane, light scattering measurements indicated cholesterol enhanced the electrostatic interaction through indirectly affecting the negatively charged phospholipid dioleoylphosphatidylserine, DOPS. Addition of PLL to lipid vesicles containing DOPS showed an initial increase in static light scattering (SLS), attributed to binding of PLL to the vesicle surface, followed by a slower continuously declining SLS signal, which, from comparison with fluorescent dye leakage studies could be attributed to vesicle lysis. Although electrostatic interactions between PLL and the membrane were not necessary for penetration to occur, cholesterol promoted membrane disruption of negatively charged vesicles, possibly by increasing the electrostatic interactions between PLL and the membrane. In contrast, cholesterol lowered the suscept...
Source: Biochimica et Biophysica Acta (BBA) Biomembranes - Category: Biochemistry Source Type: research