title: Regulation of lipid composition in Acholeplasma laidlawii and Escherichia coli membranes: NMR studies of lipid lateral diffusion at different growth temperatures.
abstract: Lipid lateral diffusion coefficients have been directly determined by pulsed field gradient NMR spectroscopy on macroscopically aligned, fully hydrated lamellar phases containing dimyristoylphosphatidylcholine and total lipid extracts from Acholeplasma laidlawii and Escherichia coli. The temperature dependence of the diffusion coefficient was of the Arrhenius type in the temperature interval studied. The sharp increase in the diffusion coefficient at the growth temperature of E. coli obtained by FRAP measurements, using a fluorescent probe molecule (Jin, A. J., Edidin, M., Nossal, R., and Gershfeld, N. L. (1999) Biochemistry 38, 13275-13278), was not observed. Thus, we conclude that the lipid structural properties (i.e., those affecting the lipid phase behavior), rather than the lipid dynamics, are involved in the adjustment of the membrane lipid composition. Further support for this conclusion is given by the finding that lipid extracts from A. laidlawii grown at different temperatures have about the same diffusion coefficients. Finally, the lipid lateral diffusion in bilayers of phospholipids was found to be much faster than that in bilayers of mainly glucolipids, which can be understood in terms of a free volume theory for the diffusion process.
authors.affiliation: Department of Biophysical Chemistry, Umeå University, SE-901 87 Umeå, Sweden. goran.lindblom@chem.umu.se
authors.forename: Göran
authors.initials: G
authors.lastname: Lindblom
authors.forename: Greger
authors.initials: G
authors.lastname: Orädd
authors.forename: Leif
authors.initials: L
authors.lastname: Rilfors
authors.forename: Sven
authors.initials: S
authors.lastname: Morein
mesh_terms: D000128:Acholeplasma laidlawii / Q000737:chemistry* / Q000254:growth & development*; D004058:Diffusion; D004926:Escherichia coli / Q000737:chemistry* / Q000254:growth & development*; D009682:Magnetic Resonance Spectroscopy; D008563:Membrane Lipids / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics
chemical_list: D008563:Membrane Lipids