화학공학소재연구정보센터
Journal of Physical Chemistry B, Vol.113, No.42, 13678-13686, 2009
Partitioning of Membrane-Anchored DNA between Coexisting Lipid Phases
The partitioning of different cholesterol-modified single-stranded DNA molecules (chol-DNA) between the domains of phase separated lipid vesicles is investigated by laser scanning confocal fluorescence microscopy. All chol-DNAs studied preferentially localized into the fluid phase of giant vesicles in liquid-solid phase coexistence (1:1 DLPC:DPPC, 1:1 DLPC:DMPE). Partitioning behavior of chol-DNAs into liquid-liquid phase-separated vesicles (DOPC/DPPC/cholesterol) was found to be less straightforward, Single-cholesterol-anchored DNA molecules partitioned roughly equally between coexisting domains, whereas chol-DNAs with two cholesterol anchors were seen to be enriched in the liquid-ordered domains with apparent surface concentrations up to double that of the liquid-disordered phase. Quantitative analysis of the fluorescence intensity of DNA between the two phases also revealed a weaker dependence of the apparent partitioning on the initial lipid composition of the vesicles. We rationalize these observations by proposing a simple partitioning model based on the coil formational entropy of insertion of a cholesterol anchor into each phase.