title: Cis and trans unsaturated phosphatidylcholine bilayers: A molecular dynamics simulation study.
abstract: Trans unsaturated lipids are uncommon in nature. In the human diet, they occur as natural products of ruminal bacteria or from industrial food processing like hydrogenation of vegetable oils. Consumption of trans unsaturated lipids has been shown to have a negative influence on human health; in particular, the risk of cardiovascular disease is higher when the amount of trans unsaturated lipids in the diet is elevated. In this study, we first performed quantum mechanical calculations to specifically and accurately parameterize cis and trans mono-unsaturated lipids and subsequently validated the newly derived parameter set. Then, we carried out molecular dynamics (MD) simulations of lipid bilayers composed of cis or trans unsaturated lipids with and without cholesterol. Our results show that trans mono-unsaturated chains are more flexible than cis mono-unsaturated chains due to lower barriers for rotation around the single bonds next to the trans double bond than those next to the cis double bond. In effect, interactions between cholesterol and trans unsaturated chains are stronger than cis unsaturated chains, which results in a higher ordering effect of cholesterol in trans unsaturated bilayers.
authors.affiliation: Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland.
authors.forename: Waldemar
authors.initials: W
authors.lastname: Kulig
authors.affiliation: Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, ul. Gronostajowa 7, 30-387 Kraków, Poland.
authors.forename: Marta
authors.initials: M
authors.lastname: Pasenkiewicz-Gierula
authors.affiliation: Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland. Electronic address: tomasz.rog@gmail.com.
authors.forename: T
authors.initials: T
authors.lastname: Róg
mesh_terms: D002784:Cholesterol / Q000737:chemistry / Q000378:metabolism; D007536:Isomerism; D008051:Lipid Bilayers / Q000737:chemistry* / Q000378:metabolism; D056004:Molecular Dynamics Simulation; D010713:Phosphatidylcholines / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D002784:Cholesterol
keywords: Cholesterol; Model validation; OPLS-AA force field; Torsional potential