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Influence of the lipid backbone on electrochemical phase behavior

DOI: 10.1021/acs.langmuir.2c02370 DOI Help

Authors: Philip N. Jemmett (University of Birmingham) , David C. Milan (University of Liverpool) , Richard J. Nichols (University of Liverpool) , Thomas Howitt (University of Birmingham) , Alexandra L. Martin (University of Birmingham) , Thomas Arnold (Diamond Light Source; European Spallation Source; ISIS Pulsed Neutron and Muon Source) , Jonathan L. Rawle (Diamond Light Source) , Christopher L. Nicklin (Diamond Light Source) , Timothy R. Dafforn (University of Birmingham) , Liam R. Cox (University of Birmingham) , Sarah L. Horswell (University of Birmingham)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Langmuir , VOL 10

State: Published (Approved)
Published: November 2022
Diamond Proposal Number(s): 15539 , 18202

Abstract: Sphingolipids are an important class of lipids found in mammalian cell membranes with important structural and signaling roles. They differ from another major group of lipids, the glycerophospholipids, in the connection of their hydrocarbon chains to their headgroups. In this study, a combination of electrochemical and structural methods has been used to elucidate the effect of this difference on sphingolipid behavior in an applied electric field. N-Palmitoyl sphingomyelin forms bilayers of similar coverage and thickness to its close analogue di-palmitoyl phosphatidylcholine. Grazing incidence diffraction data show slightly closer packing and a smaller chain tilt angle from the surface normal. Electrochemical IR results at low charge density show that the difference in tilt angle is retained on deposition to form bilayers. The bilayers respond differently to increasing electric field strength: chain tilt angles increase for both molecules, but sphingomyelin chains remain tilted as field strength is further increased. This behavior is correlated with disruption of the hydrogen-bonding network of small groups of sphingomyelin molecules, which may have significance for the behavior of molecules in lipid rafts in the presence of strong fields induced by ion gradients or asymmetric distribution of charged lipids.

Journal Keywords: Electrical properties; Lipids; Molecules; Noncovalent interactions; Vesicles

Subject Areas: Chemistry, Biology and Bio-materials

Instruments: I07-Surface & interface diffraction

Added On: 14/11/2022 08:47

Discipline Tags:

Surfaces Physical Chemistry Biochemistry Chemistry Life Sciences & Biotech

Technical Tags:

Diffraction Grazing Incidence X-ray Diffraction (GIXD) X-ray Reflectivity (XRR)