Migration of poly-L-lysine through a lipid bilayer.
When a giant vesicle, composed of neutral and anionic lipid (90:10 mol %), comes into contact with various poly-l-lysines (MW 500-29 300), ropelike structures form within the vesicle interior. By using fluorescence lipids and epi-fluorescence microscopy, we have shown that both neutral and anionic lipids are constituents of the ropes. Evidence that the ropes are also comprised of poly-l-lysine comes from two experiments: (a) direct microinjection of poly(acrylic acid) into rope-containing vesicles causes the ropes to contract into small particles, an observation consistent with a polycation/polyanion interaction; and (b) direct microinjection of fluorescein isothiocyanate (a compound that covalently labels poly-l-lysine with a fluorescent moiety) into rope-containing vesicles leads to fluorescent ropes. The results may be explained by a model in which poly-l-lysine binds to the vesicle exterior, forms a domain, and enters the vesicle through defects or at the domain boundary. The model helps explain the ability of poly-l-lysine to mediate the permeation of a cancer drug, doxorubicine, into the vesicle interior.
Menger
Fredric M
FM
Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA. menger@emory.edu
Seredyuk
Victor A
VA
Kitaeva
Marina V
MV
Yaroslavov
Alexander A
AA
Melik-Nubarov
Nickolay S
NS
D008051:Lipid Bilayers / Q000737:chemistry* / Q000378:metabolism; D008858:Microscopy, Phase-Contrast; D010713:Phosphatidylcholines / Q000737:chemistry; D010715:Phosphatidylglycerols / Q000737:chemistry; D011107:Polylysine / Q000737:chemistry* / Q000378:metabolism
D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D011107:Polylysine; C060037:1-palmitoyl-2-oleoylglycero-3-phosphoglycerol; C028694:1-palmitoyl-2-oleoylphosphatidylcholine