title: Phase Composition Control in Microsphere-Supported Biomembrane Systems.
abstract: The popularization of studies in membrane protein lipid phase coexistence has prompted the development of new techniques to construct and study biomimetic systems with cholesterol-rich lipid microdomains. Here, microsphere-supported biomembranes with integrated α-helical peptides, referred to as proteolipobeads (PLBs), were used to model peptide/protein partitioning within DOPC/DPPC/cholesterol phase-separated membranes. Due to the appearance of compositional heterogeneity and impurities in the formation of model PLB assemblies, fluorescence-activated cell sorting (FACS) was used to characterize and sort PLB populations on the basis of disordered phase (Ld) content. In addition, spectral imaging was used to assess the partitioning of FITC-labeled α-helical peptide between fluorescently labeled Ldphase and unlabeled ordered phase (Lo) phase lipid microdomains. The apparent peptide partition coefficient, Kp,app, was measured to be 0.89 ± 0.06, indicating a slight preference of the peptide for the Lophase. A biomimetic motif of the Lophase concentration enhancement of the biotinyl-peptide ligand display in proteolipobeads was also observed. Finally, peptide mobility was measured by FRAP separately in each lipid phase, yielding diffusivities of 0.036 ± 0.005 and 0.014 ± 0.003 μm2/s in the Ldand Lophases, respectively.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Fried
authors.affiliation: Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center , 1275 York Avenue, New York, New York 10065, United States.|Program of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University , New York, New York 10021, United States.
authors.forename: Yue-Ming
authors.initials: YM
authors.lastname: Li
authors.forename: M Lane
authors.identifier: 0000-0002-6247-5787
authors.initials: ML
authors.lastname: Gilchrist
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry*; D008565:Membrane Proteins / Q000737:chemistry; D018613:Microscopy, Confocal; D008863:Microspheres; D010455:Peptides / Q000737:chemistry
chemical_list: D008055:Lipids; D008565:Membrane Proteins; D010455:Peptides