Skip to Main content Skip to Navigation
Journal articles

Plant sterols: a neutron diffraction study of sitosterol and stigmasterol in soybean phosphatidylcholine membranes

Abstract : Neutron scattering experiments have been performed on oriented Soybean phosphatidylcholine (SPC) bilayers, containing sitosterol or stigmasterol, two major sterols of plant plasma membranes. Sitosterol and stigmasterol were either protonated or deuterated on position C25 of the lateral chain. Incorporation of sitosterol leads to an increase of the hydrophobic thickness of SPC bilayers of 1.2 and 2 A when present, at 16 and 30 mol%, respectively. On the other hand, no change was observed when stigmasterol is present in the bilayer at its maximal solubility of 16 mol%. These results are in agreement with the fact that sitosterol is more efficient than stigmasterol to order acyl chains of SPC, as already shown with other biophysical techniques. In order to get more insight into the behavior of the lateral chains of the two sterols, the proton-deuterium contrast method was used in order to locate the (2)H25 atoms of the two sterols. For sitosterol, this atom was found close to the center of the bilayer at +/-(1.6+/-0.2 A), with a width, nu=2.5+/-0.5 A. For stigmasterol, the difference profile could be fitted in two different ways: either two possible locations are found at +/-(2.3+/-0.2 A) and +/-(10+/-0.2 A) with the same width, nu=2.5+/-0.5 A or only one broad distribution at +/-(6.1+/-0.3 A), nu=8.5+/-0.7 A. The results are discussed in terms of difference of dynamics for the lateral chain of the two sterols.
Document type :
Journal articles
Complete list of metadatas

https://www.hal.inserm.fr/inserm-02472278
Contributor : Mary Poupot <>
Submitted on : Monday, February 10, 2020 - 10:15:54 AM
Last modification on : Thursday, November 19, 2020 - 2:44:19 PM

Links full text

Identifiers

Collections

Citation

M.P. Marsan, E. Bellet-Amalric, I. Muller, G. Zaccai, A. Milon. Plant sterols: a neutron diffraction study of sitosterol and stigmasterol in soybean phosphatidylcholine membranes. Biophysical Chemistry, Elsevier, 1998, 75 (1), pp.45-55. ⟨10.1016/s0301-4622(98)00188-4⟩. ⟨inserm-02472278⟩

Share

Metrics

Record views

303