TY - JOUR
T1 - Joint small-angle X-ray and neutron scattering data analysis of asymmetric lipid vesicles
AU - Eicher, Barbara
AU - Heberle, Frederick A.
AU - Marquardt, Drew
AU - Rechberger, Gerald N.
AU - Katsaras, John
AU - Pabst, Georg
N1 - Publisher Copyright:
© 2017 Barbara Eicher et al.
PY - 2017
Y1 - 2017
N2 - Low- and high-resolution models describing the internal transbilayer structure of asymmetric lipid vesicles have been developed. These models can be used for the joint analysis of small-angle neutron and X-ray scattering data. The models describe the underlying scattering length density/electron density profiles either in terms of slabs or through the so-called scattering density profile, previously applied to symmetric lipid vesicles. Both models yield structural details of asymmetric membranes, such as the individual area per lipid, and the hydrocarbon thickness of the inner and outer bilayer leaflets. The scattering density profile model, however, comes at a cost of increased computational effort but results in greater structural resolution, showing a slightly lower packing of lipids in the outer bilayer leaflet of ∼120 nm diameter palmitoyloleoyl phosphatidylcholine (POPC) vesicles, compared to the inner leaflet. Analysis of asymmetric dipalmitoyl phosphatidylcholine/POPC vesicles did not reveal evidence of transbilayer coupling between the inner and outer leaflets at 323 K, i.e. above the melting transition temperature of the two lipids.
AB - Low- and high-resolution models describing the internal transbilayer structure of asymmetric lipid vesicles have been developed. These models can be used for the joint analysis of small-angle neutron and X-ray scattering data. The models describe the underlying scattering length density/electron density profiles either in terms of slabs or through the so-called scattering density profile, previously applied to symmetric lipid vesicles. Both models yield structural details of asymmetric membranes, such as the individual area per lipid, and the hydrocarbon thickness of the inner and outer bilayer leaflets. The scattering density profile model, however, comes at a cost of increased computational effort but results in greater structural resolution, showing a slightly lower packing of lipids in the outer bilayer leaflet of ∼120 nm diameter palmitoyloleoyl phosphatidylcholine (POPC) vesicles, compared to the inner leaflet. Analysis of asymmetric dipalmitoyl phosphatidylcholine/POPC vesicles did not reveal evidence of transbilayer coupling between the inner and outer leaflets at 323 K, i.e. above the melting transition temperature of the two lipids.
KW - asymmetric membranes
KW - joint SAXS/SANS analysis
KW - lipid bilayers
KW - scattering density profile models
KW - small-angle X-ray scattering (SAXS)
KW - small-angle neutron scattering (SANS)
KW - transbilayer coupling
UR - http://www.scopus.com/inward/record.url?scp=85017132359&partnerID=8YFLogxK
U2 - 10.1107/S1600576717000656
DO - 10.1107/S1600576717000656
M3 - Article
AN - SCOPUS:85017132359
SN - 0021-8898
VL - 50
SP - 419
EP - 429
JO - Journal of Applied Crystallography
JF - Journal of Applied Crystallography
ER -