title: Spontaneously forming ellipsoidal phospholipid unilamellar vesicles and their interactions with helical domains of saposin C.
abstract: We have observed a bimodal distribution of ellipsoidal unilamellar vesicles (ULVs) in a phospholipid mixture composed of dioleoyl phosphatidylserine (DOPS) and dipalmitoyl and dihexanoyl phosphatidylcholine, DPPC and DHPC, respectively. Dynamic light scattering and transmission electron microscopy data indicate a bimodal size distribution of these nanoparticles with hydrodynamic radii of approximately 200 and >500 nm, while small-angle neutron scattering data were fit using a model of coexisting monodisperse morphologies, namely, oblate and triaxial ellipsoidal vesicles. Unlike DOPS ULV formed by sonication, which can fuse days after being formed, these ULVs are stable over a period of 12 months at 4 degrees C. We also report on the structure of these ULVs associated with the two helical peptide domains (H1 and H2) of a glucosylprotein, namely, Saposin C, to gain some insight into protein-membrane interactions.
authors.affiliation: Canadian Neutron Beam Center, Steacie Institute for Molecular Sciences, National Research Council at Canada, Chalk River, Ontario, Canada K0J-1J0. mu-ping.nieh@nrc.gc.ca
authors.forename: Mu-Ping
authors.initials: MP
authors.lastname: Nieh
authors.forename: Jeremy
authors.initials: J
authors.lastname: Pencer
authors.forename: John
authors.initials: J
authors.lastname: Katsaras
authors.forename: Xiaoyang
authors.initials: X
authors.lastname: Qi
mesh_terms: D000818:Animals; D010743:Phospholipids / Q000737:chemistry*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D049231:Saposins / Q000737:chemistry*; D053835:Unilamellar Liposomes / Q000737:chemistry*
chemical_list: D010743:Phospholipids; D049231:Saposins; D053835:Unilamellar Liposomes