Investigation on the relationship between lipid composition and structure in model membranes composed of extracted
Andreas Santamaria1, Krishna C Batchu2, Giovanna Fragneto3
1Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble, Cedex 9, France; Departamento de Química Física, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain.
Hypothesis:
Unravelling the structural diversity of cellular membranes is a paramount challenge in life sciences. In particular, lipid composition affects the membrane collective behaviour, and its interactions with other biological molecules.
Experiments:
Here, the relationship between membrane composition and resultant structural features was investigated by surface pressure-area isotherms, Brewster angle microscopy and neutron reflectometry on in vitro membrane models of the mammalian plasma and endoplasmic-reticulum-Golgi intermediate compartment membranes in the form of Langmuir monolayers. Natural extracted yeast lipids were used because, unlike synthetic lipids, the acyl chain saturation pattern of yeast and mammalian lipids are similar.
Findings:
The structure of the model membranes, orthogonal to the plane of the membrane, as well as their lateral packing, were found to depend strongly on their specific composition, with cholesterol having a major influence on the in-plane morphology, yielding a coexistence of liquid-order and liquid-disorder phases.
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