title: Lipid dynamics in fast-tumbling bicelles with varying bilayer thickness: effect of model transmembrane peptides.
abstract: The morphology of q=0.5 fast-tumbling bicelles prepared with three different acyl chain lengths has been investigated by NMR. It is shown that bicelles prepared with DLPC (12 C) and DHPC are on average larger than those containing DMPC or DPPC (14 and 16 C) and DHPC, which may be due to a higher degree of mixing between DLPC and DHPC. The fast internal mobility of the lipids was determined from natural abundance carbon-13 relaxation. A similar dynamical behaviour of the phospholipids in the three different bicelles was observed, although the DPPC lipid acyl chain displayed a somewhat lower degree of mobility, as evidenced by higher generalized order parameters throughout the acyl chain. Carbon-13 relaxation was also used to determine the effect of different model transmembrane peptides, with flanking Lys residues, on the lipid dynamics in the three different bicelles. All peptides had the effect of increasing the order parameters for the DLPC lipid, while no effect was observed on the longer lipid chains. This effect may be explained by a mismatch between the hydrophobic length of the peptides and the DLPC lipid acyl chain.
authors.affiliation: Center for Biomembrane Research, Department of Biochemistry and Biophysics, The Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden.
authors.forename: Jesper
authors.initials: J
authors.lastname: Lind
authors.forename: Jon
authors.initials: J
authors.lastname: Nordin
authors.forename: Lena
authors.initials: L
authors.lastname: Mäler
mesh_terms: D000595:Amino Acid Sequence; D055592:Biophysical Phenomena; D002462:Cell Membrane / Q000737:chemistry*; D002942:Circular Dichroism; D004058:Diffusion; D008051:Lipid Bilayers / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D013696:Temperature
chemical_list: D008051:Lipid Bilayers; D010455:Peptides