title: Acidic phospholipid bicelles: a versatile model membrane system.
abstract: With the aim of establishing acidic bicellar solutions as a useful membrane model system, we have used deuterium NMR spectroscopy to investigate the properties of dimyristoyl/dihexanoylphosphatidylcholine (DMPC/DHPC) bicelles containing 25% (w/w in H(2)O) of either dimyristoylphosphatidylserine (DMPS) or dimyristoylphosphatidylglycerol (DMPG). The addition of the acidic lipid component to this lyotropic liquid crystalline system reduces its range of stability because of poor miscibility of the two dimyristoylated phospholipids. Compared to the neutral bicelles, which are stable at pH 4 to pH 7, acidic bicelles are stable only from pH 5.5 to pH 7. Solid-state deuterium NMR analysis of d(54)-DMPC showed similar ordering in neutral and acidic bicelles. Fully deuterated DMPS or DMPG is ordered in a way similar to that of DMPC. Study of the binding of the myristoylated N-terminal 14-residue peptide mu-GSSKSKPKDPSQRR from pp60(nu-src) to both neutral and acidic bicelles shows the utility of these novel membrane mimetics.
authors.affiliation: Department of Chemistry, University of California San Diego, La Jolla, California 92093-0359 USA. ekomives@ucsd.edu
authors.forename: J
authors.initials: J
authors.lastname: Struppe
authors.forename: J A
authors.initials: JA
authors.lastname: Whiles
authors.forename: R R
authors.initials: RR
authors.lastname: Vold
mesh_terms: D000595:Amino Acid Sequence; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D004355:Drug Stability; D008051:Lipid Bilayers / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D010455:Peptides / Q000737:chemistry*; D010715:Phosphatidylglycerols / Q000737:chemistry; D010742:Phospholipid Ethers / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry*; D013329:Structure-Activity Relationship; D013816:Thermodynamics; D014867:Water
chemical_list: C052298:1,2-dihexadecyl-sn-glycero-3-phosphocholine; D008051:Lipid Bilayers; D008823:Micelles; D010455:Peptides; D010715:Phosphatidylglycerols; D010742:Phospholipid Ethers; D010743:Phospholipids; D014867:Water; C002773:dimyristoylphosphatidylglycerol; D004134:Dimyristoylphosphatidylcholine