title: Molecular aspects of the interaction between plants sterols and DPPC bilayers: an experimental and theoretical approach.
abstract: The effect of sterols composition in a lipid bilayer was investigated on membranes of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and mixtures with the plant sterols β-sitosterol and stigmasterol. Differential scanning calorimetry, 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence polarization and infrared spectroscopy studies showed that both sterols changed the packing of the membrane and the hydration of the polar headgroup of the phospholipids, disordering the gel phase and, vice versa, ordering the membrane in the liquid crystalline phase. In all cases some differences among β-sitosterol and stigmasterol could be observed, being β-sitosterol slightly more efficient than stigmasterol in ordering a fluid membrane, bringing the membrane to a more packed liquid ordered phase. Molecular dynamic simulations were carried out to better characterize the distinct behavior of both sterols in a DPPC-membrane. The calculated parameters agreed quite well with the experimental results and a molecular model is proposed to explain differences in the sterols molecules and their effect on the DPPC-bilayer.
authors.affiliation: Facultad de Ciencias Agronómicas, Departamento de Recursos Ambientales, Universidad de Tarapacá, Arica, Chile.
authors.forename: Claudia
authors.initials: C
authors.lastname: Silva
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Aranda
authors.forename: Antonio
authors.initials: A
authors.lastname: Ortiz
authors.forename: Vicente
authors.initials: V
authors.lastname: Martínez
authors.forename: Micaela
authors.initials: M
authors.lastname: Carvajal
authors.forename: José A
authors.initials: JA
authors.lastname: Teruel
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D004058:Diffusion; D005454:Fluorescence Polarization; D008051:Lipid Bilayers / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D010944:Plants / Q000737:chemistry*; D012855:Sitosterols / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013265:Stigmasterol / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D012855:Sitosterols; D015060:1,2-Dipalmitoylphosphatidylcholine; C025473:gamma-sitosterol; D013265:Stigmasterol