%0 Journal Article
%A de Santis, Augusta
%A Vitiello, Giuseppe
%A Appavou, Marie-Sousai
%A Scoppola, Ernesto
%A Fragneto, Giovanna
%A Barnsley, Lester C.
%A Clifton, Luke A.
%A Ottaviani, Maria Francesca
%A Paduano, Luigi
%A Russo Krauss, Irene
%A D’Errico, Gerardino
%T Not just a fluidifying effect: omega-3 phospholipids induce formation of non-lamellar structures in biomembranes
%J Soft matter
%V 16
%N 46
%@ 1744-6848
%C London
%I Royal Soc. of Chemistry
%M FZJ-2020-04861
%P 10425-10438
%D 2020
%X Polyunsaturated omega-3 fatty acid docosahexaenoic acid (DHA) is found in very high concentrations in a few peculiar tissues, suggesting that it must have a specialized role. DHA was proposed to affect the function of the cell membrane and related proteins through an indirect mechanism of action, based on the DHA-phospholipid effects on the lipid bilayer structure. In this respect, most studies have focused on its influence on lipid-rafts, somehow neglecting the analysis of effects on liquid disordered phases that constitute most of the cell membranes, by reporting in these cases only a general fluidifying effect. In this study, by combining neutron reflectivity, cryo-transmission electron microscopy, small angle neutron scattering, dynamic light scattering and electron paramagnetic resonance spectroscopy, we characterize liquid disordered bilayers formed by the naturally abundant 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and different contents of a di-DHA glycero-phosphocholine, 22:6-22:6PC, from both a molecular/microscopic and supramolecular/mesoscopic viewpoint. We show that, below a threshold concentration of about 40% molar percent, incorporation of 22:6-22:6PC in the membrane increases the lipid dynamics slightly but sufficiently to promote the membrane deformation and increase of multilamellarity. Notably, beyond this threshold, 22:6-22:6PC disfavours the formation of lamellar phases, leading to a phase separation consisting mostly of small spherical particles that coexist with a minority portion of a lipid blob with water-filled cavities. Concurrently, from a molecular viewpoint, the polyunsaturated acyl chains tend to fold and expose the termini to the aqueous medium. We propose that this peculiar tendency is a key feature of the DHA-phospholipids making them able to modulate the local morphology of biomembranes.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ 33165495
%U <Go to ISI:>//WOS:000596710100004
%R 10.1039/D0SM01549K
%U https://juser.fz-juelich.de/record/888343