Induction of lipid flip-flop by colicin E1 - a hallmark of proteolipidic pore formation in liposome membranes.
The addition of the channel-forming domain of colicin E1 to liposomes elicited the transmembrane diffusion (flip-flop) of lipids concomitant to the release of the fluorescent dye from liposomes. Good correlation was found between kinetic and concentration dependences of the two processes. Both the liposome leakage and the lipid flip-flop were stimulated upon alkalinization of the buffer solution after colicin binding at acidic pH. These results in combination with the analysis of the data on colicin binding to liposomes provide evidence in favor of the validity of the toroidal (proteolipidic) pore model as the mechanism of colicin channel formation.
Sobko
A A
AA
Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Russia. sobko@genebee.msu.ru
Kovalchuk
S I
SI
Kotova
E A
EA
Antonenko
Y N
YN
D003087:Colicins / Q000378:metabolism*; D004058:Diffusion; D005456:Fluorescent Dyes / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008055:Lipids / Q000737:chemistry*; D008081:Liposomes / Q000378:metabolism*; D011485:Protein Binding; D013050:Spectrometry, Fluorescence
D003087:Colicins; D005456:Fluorescent Dyes; D008055:Lipids; D008081:Liposomes