Micromolar concentrations of Zn2+ potentiates Ca2+-induced phase separation of phosphatidyl serine containing liposomes.
Fluorescence quenching of 1-acyl-2-[6[(7 nitro-2,1,3-benzoxadiazol-4yl) amino]caproyl] phosphatidyl choline in small unilamellar vesicles consisting of phosphatidyl serine has been used to monitor the lipid phase separation induced by Zn2+ and Ca2+. Phase separation of vesicle membranes was observed with Zn2+ at concentrations as low as 125 microM. Low concentrations of Zn2+ required long incubation times to reach maximal quenching (120 minutes at 375 microM). When low concentrations of Ca2+ were added to the preparation during the developing phase of Zn2+-induced quenching, an explosive increase in fluorescence quenching was instantenously observed. Phase separation induced by sub-millimolar concentrations of Ca2+ could be increased at least 4 times when vesicles were pre-incubated with 250 microM of Zn2+.
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M
Deleers
J P
JP
Servais
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E
Wulfert
D009327:4-Chloro-7-nitrobenzofurazan / Q000031:analogs & derivatives; D002118:Calcium / Q000494:pharmacology*; D004357:Drug Synergism; D005456:Fluorescent Dyes; D007700:Kinetics; D008051:Lipid Bilayers; D008081:Liposomes; D010713:Phosphatidylcholines; D010718:Phosphatidylserines; D013050:Spectrometry, Fluorescence; D015032:Zinc / Q000494:pharmacology*
D005456:Fluorescent Dyes; D008051:Lipid Bilayers; D008081:Liposomes; D010713:Phosphatidylcholines; D010718:Phosphatidylserines; D009327:4-Chloro-7-nitrobenzofurazan; D015032:Zinc; D002118:Calcium