Localization of Cholesterol within Supported Lipid Bilayers Made of a Natural Extract of Tailor-Deuterated Phosphatidylcholine

TY - JOUR

T1 - Localization of Cholesterol within Supported Lipid Bilayers Made of a Natural Extract of Tailor-Deuterated Phosphatidylcholine

AU - Waldie, Sarah

AU - Lind, Tania Kjellerup

AU - Browning, Kathryn

AU - Moulin, Martine

AU - Haertlein, Michael

AU - Forsyth, V. Trevor

AU - Luchini, Alessandra

AU - Strohmeier, Gernot A.

AU - Pichler, Harald

AU - Maric, Selma

AU - Cárdenas, Marité

PY - 2018

Y1 - 2018

N2 - Cholesterol is an essential component of mammalian membranes and is known to induce a series of physicochemical changes in the lipid bilayer. Such changes include the formation of liquid-ordered phases with an increased thickness and a configurational order as compared to liquid-disordered phases. For saturated lipid membranes, cholesterol molecules localize close to the lipid head group-tail interface. However, the presence of polyunsaturated lipids was recently shown to promote relocation of cholesterol toward the inner interface between the two bilayer leaflets. Here, neutron reflection is used to study the location of cholesterol (both non-deuterated and per-deuterated versions are used) within supported lipid bilayers composed of a natural mixture of phosphatidylcholine (PC). The lipids were produced in a genetically modified strain of Escherichia coli and grown under specific deuterated conditions to give an overall neutron scattering length density (which depends on the level of deuteration) of the lipids matching that of D2O. The combination of solvent contrast variation method with specific deuteration shows that cholesterol is located closer to the lipid head group-tail interface in this natural PC extract rather than in the center of the core of the bilayer as seen for very thin or polyunsaturated membranes.

AB - Cholesterol is an essential component of mammalian membranes and is known to induce a series of physicochemical changes in the lipid bilayer. Such changes include the formation of liquid-ordered phases with an increased thickness and a configurational order as compared to liquid-disordered phases. For saturated lipid membranes, cholesterol molecules localize close to the lipid head group-tail interface. However, the presence of polyunsaturated lipids was recently shown to promote relocation of cholesterol toward the inner interface between the two bilayer leaflets. Here, neutron reflection is used to study the location of cholesterol (both non-deuterated and per-deuterated versions are used) within supported lipid bilayers composed of a natural mixture of phosphatidylcholine (PC). The lipids were produced in a genetically modified strain of Escherichia coli and grown under specific deuterated conditions to give an overall neutron scattering length density (which depends on the level of deuteration) of the lipids matching that of D2O. The combination of solvent contrast variation method with specific deuteration shows that cholesterol is located closer to the lipid head group-tail interface in this natural PC extract rather than in the center of the core of the bilayer as seen for very thin or polyunsaturated membranes.

U2 - 10.1021/acs.langmuir.7b02716

DO - 10.1021/acs.langmuir.7b02716

M3 - Journal article

C2 - 29232134

AN - SCOPUS:85040308496

SN - 0743-7463

VL - 34

SP - 472

EP - 479

JO - Langmuir

JF - Langmuir

IS - 1

ER -