Measuring raft size as a function of membrane composition in PC-based systems: Part 1--binary systems.
This work applied two steady-state fluorescence techniques to detect nanoscopic membrane domains in a binary dimyristoylphosphocholine (DMPC)-cholesterol system and a ternary dioleoylphosphocholine (DOPC)-dipalmitoylphosphocholine (DPPC)-cholesterol system. A polarity-induced spectral shift in the emission spectra of 1-myristoyl-2-[12-[(5-dimethylamino-1-naphthalenesulfonyl)amino]dodecanoyl]-sn-glycero-3-phosphocholine (DAN-PC) in combination with a Förster resonance energy transfer (FRET) assay agreed with the phase diagrams that have been published for these systems and were observed to be useful tools in the detection of membrane heterogeneities. The DAN-PC/dehydroergosterol (DHE) FRET pair was found to be best suited for use with these steady-state techniques because of their differential partitioning between phases, although a high acceptor concentration was needed to obtain accurate measurements. In the binary system, this high probe concentration was found to be perturbing, but in more representative ternary systems, the high probe concentration no longer disrupted the phase behavior of the system. This FRET pair allowed for the calculation of nanometer-scale domain sizes in model ternary systems, using the two steady-state fluorescence techniques along with a clear and straightforward model.
Brown
Angela C
AC
Department of Chemical and Biological Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104, USA.
Towles
Kevin B
KB
Wrenn
Steven P
SP
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D002784:Cholesterol / Q000737:chemistry; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D004735:Energy Transfer; D031541:Fluorescence Resonance Energy Transfer; D005456:Fluorescent Dyes; D054709:Lecithins / Q000737:chemistry*; D021962:Membrane Microdomains / Q000737:chemistry*; D008567:Membranes, Artificial; D008956:Models, Chemical; D036103:Nanotechnology; D010713:Phosphatidylcholines / Q000737:chemistry; D013050:Spectrometry, Fluorescence
D005456:Fluorescent Dyes; D054709:Lecithins; D008567:Membranes, Artificial; D010713:Phosphatidylcholines; C069347:1-O-(N-dansyl-11-amino-1-undecyl)-2-O-decanoylphosphatidylcholine; D015060:1,2-Dipalmitoylphosphatidylcholine; D002784:Cholesterol; C017251:1,2-oleoylphosphatidylcholine; D004134:Dimyristoylphosphatidylcholine