title: Structural properties of the water/membrane interface of a bilayer built of the E. coli lipid A.
abstract: Lipid A is the most chemically invariant part of lipopolysaccharides (LPS). Both lipid A and LPS constitute the external layer of the outer membrane of Gram-negative bacteria. E. coli-specific hexacyl lipid A (ECLA) forms stable bilayers in the presence of sodium or magnesium cations. To characterize biologically relevant properties of the ECLA bilayer, and in particular its water/membrane interface, 800 ns molecular dynamics (MD) simulations of fully hydrated bilayers made of ECLA at 50 °C (i.e., 6 °C above the main phase transition) were performed. The validation of the computer model for the ECLA bilayer was performed using available experimental data. The overall good agreement with the data was found. An ECLA molecule makes on average ∼1.3 ion-mediated bridges with neighboring lipid molecules. The average number of interlipid hydrogen bonds is 2.7. The abundance of such intermolecular links results in tight packing of ECLA molecules in the bilayer and explains the relatively small value of the surface area per lipid (1.515 nm(2)).
authors: Department of Computational Biophysics and Bioinformatics, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Kraków, Poland.
authors: Krzysztof
authors: K
authors: Murzyn
authors: Department of Computational Biophysics and Bioinformatics, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, Kraków, Poland.
authors: Marta
authors: M
authors: Pasenkiewicz-Gierula
mesh_terms: D004583:Electrons; D004926:Escherichia coli; D029968:Escherichia coli Proteins / Q000737:chemistry*; D006860:Hydrogen Bonding; D007477:Ions / Q000737:chemistry; D008050:Lipid A / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D011487:Protein Conformation; D012964:Sodium / Q000737:chemistry; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry*
chemical_list: D029968:Escherichia coli Proteins; D007477:Ions; D008050:Lipid A; D008051:Lipid Bilayers; D014867:Water; D012964:Sodium