title: Multi-component modeling of quasielastic neutron scattering from phospholipid membranes.
abstract: We investigated molecular motions in the 0.3-350 ps time range of D2O-hydrated bilayers of 1-palmitoyl-oleoyl-sn-glycero-phosphocholine and 1,2-dimyristoyl-sn-glycero-phosphocholine in the liquid phase by quasielastic neutron scattering. Model analysis of sets of spectra covering scale lengths from 4.8 to 30 Å revealed the presence of three types of motion taking place on well-separated time scales: (i) slow diffusion of the whole phospholipid molecules in a confined cylindrical region; (ii) conformational motion of the phospholipid chains; and (iii) fast uniaxial rotation of the hydrogen atoms around their carbon atoms. Based on theoretical models for the hydrogen dynamics in phospholipids, the spatial extent of these motions was analysed in detail and the results were compared with existing literature data. The complex dynamics of protons was described in terms of elemental dynamical processes involving different parts of the phospholipid chain on whose motions the hydrogen atoms ride.
authors.affiliation: Dipartimento di Fisica e Scienze della Terra, University of Messina, I-98166 Messina, Italy.
authors.forename: U
authors.initials: U
authors.lastname: Wanderlingh
authors.affiliation: Dipartimento di Fisica e Scienze della Terra, University of Messina, I-98166 Messina, Italy.
authors.forename: G
authors.initials: G
authors.lastname: D'Angelo
authors.affiliation: Dipartimento di Fisica e Scienze della Terra, University of Messina, I-98166 Messina, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Branca
authors.affiliation: Institute for Physical Chemistry II, Ruhr-University Bochum, Bochum, Germany.
authors.forename: V Conti
authors.initials: VC
authors.lastname: Nibali
authors.affiliation: Dipartimento di Fisica e Scienze della Terra, University of Messina, I-98166 Messina, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Trimarchi
authors.affiliation: Dipartimento di Fisica e Scienze della Terra, University of Messina, I-98166 Messina, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Rifici
authors.affiliation: Dipartimento di Fisica e Scienze della Terra, University of Messina, I-98166 Messina, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Finocchiaro
authors.affiliation: IPCF-V.le F. Stagno D'Alcontres, n. 37, Messina 98158, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Crupi
authors.affiliation: Institut Laue-Langevin, 6 rue J. Horowitz, BP 156, F-38042 Grenoble, France.
authors.forename: J
authors.initials: J
authors.lastname: Ollivier
authors.affiliation: Clarendon Laboratory, University of Oxford, Oxford, United Kingdom.
authors.forename: H D
authors.initials: HD
authors.lastname: Middendorf
mesh_terms: D002244:Carbon / Q000737:chemistry; D004058:Diffusion; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D008566:Membranes / Q000737:chemistry*; D008968:Molecular Conformation; D033363:Neutron Diffraction; D010743:Phospholipids / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D010743:Phospholipids; D002244:Carbon; D004134:Dimyristoylphosphatidylcholine