title: Effects and Location of Coplanar and Noncoplanar PCB in a Lipid Bilayer: A Solid-State NMR Study.
abstract: Coplanar and noncoplanar polychlorinated biphenyls (PCBs) are known to have different routes and degree of toxicity. Here, the effects of noncoplanar PCB 52 and coplanar PCB 77 present at 2 mol % in a model system consisting of POPC liposomes (50% hydrated) are investigated by solid-state (13)C and (31)P NMR at 298 K. Both PCBs intercalate horizontally in the outer part of the bilayer, near the segments of the acyl chain close to the glycerol group. Despite similar membrane locations, the coplanar PCB 77 shows little effect on the bilayer properties overall, except for the four nearest neighboring lipids, while the effect of PCB 52 is more dramatic. The first ∼2 layers of lipids around each PCB 52 in the bilayer form a high fluidity lamellar phase, whereas lipids beyond these layers form a lamellar phase with a slight increase in fluidity compared to a bilayer without PCB 52. Further, a third high mobility domain is observed. The explanation for this is the interference of several high fluidity lamellar phases caused by interactions of PCB 52 molecules in different leaflets of the model bilayer. This causes formation of high curvature toroidal region in the bilayer and might induce formation of channels.
authors.affiliation: Department of Chemistry, University of Bergen, Norway , Allégaten 41, N-5007 Bergen, Norway.
authors.forename: Christian
authors.initials: C
authors.lastname: Totland
authors.affiliation: Department of Chemistry, University of Bergen, Norway , Allégaten 41, N-5007 Bergen, Norway.
authors.forename: Willy
authors.initials: W
authors.lastname: Nerdal
authors.affiliation: Department of Biomedical Laboratory Sciences and Chemical Engineering, Bergen University College , 5020 Bergen, Norway.
authors.forename: Signe
authors.initials: S
authors.lastname: Steinkopf
mesh_terms: D008051:Lipid Bilayers; D011078:Polychlorinated Biphenyls
chemical_list: D008051:Lipid Bilayers; D011078:Polychlorinated Biphenyls