How does ytterbium chloride interact with DMPC bilayers?:A computational and experimental study

Gonzalez, Miguel A. and Barriga, Hanna M.G. and Richens, Joanna L. and Law, Robert V. and O'Shea, Paul and Bresme, Fernando (2017) How does ytterbium chloride interact with DMPC bilayers?:A computational and experimental study. Physical Chemistry Chemical Physics, 19 (13). pp. 9199-9209. ISSN 1463-9076

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Abstract

Lanthanide salts have been studied for many years, primarily in NMR experiments of mixed lipid-protein systems and more recently to study lipid flip-flop in model membrane systems. It is well recognised that lanthanide salts can influence the behaviour of both lipid and protein systems, however a full molecular level description of lipid-lanthanide interactions is still outstanding. Here we present a study of lanthanide-bilayer interactions, using molecular dynamics computer simu-lations, fluorescence electrostatic potential experiments and Nuclear Magnetic Resonance. Com-puter simulations reveal the microscopic structure of DMPC lipid bilayers in the presence of Yb 3+ , and a surprising ability of the membranes to adsorb significant concentrations of Yb 3+ without significant disruption of the overall membrane structure. The Yb 3+ ions bind strongly to the lipids via the oxygen atoms in the lipid head group. We find that the cations are coordinated to 4-5 lipids for a wide range of Lanthanide:lipid ratios and temperatures. Addition of Yb 3+ results in a small decrease of the area per lipid with a concomitant increase of the ordering of the aliphatic chains and the bilayer thickness. The addition of Yb 3+ at standard concentrations commonly used in the NMR, induces an increase of the membrane electrostatic potential, ∼ 110 mV and a large change in the head-group orientation, which aligns in the direction normal to the bilayer plane. In addition the area compressibility modulus (stiffness) of DMPC having Ytterbium salt is 2.6 time higher than the membrane free-salt. These changes in the membrane properties are enhanced with salt con-centration, and should be taken into account in the interpretation of NMR experiments performed with Lanthanides.

Item Type:
Journal Article
Journal or Publication Title:
Physical Chemistry Chemical Physics
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1600/1606
Subjects:
ID Code:
126028
Deposited By:
Deposited On:
11 Jul 2018 13:50
Refereed?:
Yes
Published?:
Published
Last Modified:
27 Feb 2020 04:23