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Fast-tumbling bicelles constructed from native Escherichia coli lipids

J. Liebau ; P. Pettersson ; P. Zuber ; Candan Ariöz (Institutionen för biologi och bioteknik, Kemisk biologi) ; L. Maler
Biochimica Et Biophysica Acta-Biomembranes (0005-2736). Vol. 1858 (2016), 9, p. 2097-2105.
[Artikel, refereegranskad vetenskaplig]

Solution-state NMR requires small membrane mimetic systems to allow for acquiring high-resolution data. At the same time these mimetics should faithfully mimic biological membranes. Here we characterized two novel fast-tumbling bicelle systems with lipids from two Escherichia coli strains. While strain 1 (AD93WT) contains a characteristic E. coli lipid composition, strain 2 (AD93-PE) is not capable of synthesizing the most abundant lipid in E. coli, phosphatidylethanolamine. The lipid and acyl chain compositions were characterized by P-31 and C-13 NMR. Depending on growth temperature and phase, the lipid composition varies substantially, which means that the bicelle composition can be tuned by using lipids from cells grown at different temperatures and growth phases. The hydrodynamic radii of the bicelles were determined from translational diffusion coefficients and NMR spin relaxation was measured to investigate lipid properties in the bicelles. We find that the lipid dynamics are unaffected by variations in lipid composition, suggesting that the bilayer is in a fluid phase under all conditions investigated here. Backbone glycerol carbons are the most rigid positions in all lipids, while head-group carbons and the first carbons of the acyl chain are somewhat more flexible. The flexibility increases down the acyl chain to almost unrestricted motion at its end. Carbons in double bonds and cyclopropane moieties are substantially restricted in their motional freedom. The bicelle systems characterized here are thus found to faithfully mimic E. coli inner membranes and are therefore useful for membrane interaction studies of proteins with E. coli inner membranes by solution-state NMR. (C) 2016 Elsevier B.V. All rights reserved.

Nyckelord: Native lipids, Bicelle, Model-free approach, Dynamics, Diffusion, Inner membrane, Lipid composition, cyclopropane fatty-acids, magnetic-resonance relaxation, model membrane, system, translational diffusion, phospholipid bicelles, cardiolipin, synthesis, pressure resistance, isotropic bicelles, micellar-solutions, growth-phase, Biochemistry & Molecular Biology, Biophysics, chavigny a, 1991, journal of biological chemistry, v266, p5323, mendoza d, 1983, trends in biochemical sciences, v8, p49, ejskal eo, 1965, journal of chemical physics, v42, p288



Denna post skapades 2016-09-07.
CPL Pubid: 241423

 

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Institutioner (Chalmers)

Institutionen för biologi och bioteknik, Kemisk biologi

Ämnesområden

Biofysik

Chalmers infrastruktur