Fast-tumbling bicelles constructed from native Escherichia coli lipids

• 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.

Ämnesord

NATURVETENSKAP  -- Biologi -- Biofysik (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biophysics (hsv//eng)

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Nyckelord

p288

p49

1983

Bicelle

Native lipids

model membrane

1965

v266

v8

magnetic-resonance relaxation

journal of chemical physics

Lipid composition

isotropic bicelles

mendoza d

translational diffusion

pressure resistance

phospholipid bicelles

v42

cyclopropane fatty-acids

micellar-solutions

trends in biochemical sciences

ejskal eo

Biochemistry & Molecular Biology

Diffusion

Model-free approach

cardiolipin

system

Biophysics

journal of biological chemistry

Dynamics

chavigny a

Inner membrane

growth-phase

synthesis

1991

p5323

Biophysics

Publikations- och innehållstyp

art (ämneskategori)

ref (ämneskategori)