title: Thermotropic and structural effects of poly(malic acid) on fully hydrated multilamellar DPPC-water systems.
abstract: The thermotropic and structural effects of low molecular weight poly(malic acid) (PMLA) on fully hydrated multilamellar dipalmitoylphosphatidylcholine (DPPC)-water systems were investigated using differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), and freeze-fracture transmission electron microscopy (FFTEM). Systems of 20wt% DPPC concentration and 1 and 5wt% PMLA to lipid ratios were studied. The PMLA derivatives changed the thermal behavior of DPPC significantly and caused a drastic loss in correlation between lamellae in the three characteristic thermotropic states (i.e., in the gel, rippled gel and liquid crystalline phases). In the presence of PBS or NaCl, the perturbation was more moderate. The structural behavior on the atomic level was revealed by FTIR spectroscopy. The molecular interactions between DPPC and PMLA were simulated via modeling its measured infrared spectra, and their peculiar spectral features were interpreted. Through this interpretation, the poly(malic acid) is inferred to attach to the headgroups of the phospholipids through hydrogen bonds between the free hydroxil groups of PMLA and the phosphodiester groups of DPPC.
authors.affiliation: Research Center for Natural Sciences, Hungarian Academy of Sciences, Institute of Molecular Pharmacology, Dept. of Biological Nanochemistry, 1025 Budapest, Pusztaszeri út 59-67, Hungary. berenyi.szilvia@ttk.mta.hu
authors.forename: Szilvia
authors.initials: S
authors.lastname: Berényi
authors.forename: Judith
authors.initials: J
authors.lastname: Mihály
authors.forename: Sándor
authors.initials: S
authors.lastname: Kristyán
authors.forename: Lívia
authors.initials: L
authors.lastname: Naszályi Nagy
authors.forename: Judit
authors.initials: J
authors.lastname: Telegdi
authors.forename: Attila
authors.initials: A
authors.lastname: Bóta
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D001671:Biochemistry / Q000379:methods; D002152:Calorimetry, Differential Scanning; D003198:Computer Simulation; D016503:Drug Delivery Systems; D005614:Freeze Fracturing; D005782:Gels / Q000737:chemistry; D006860:Hydrogen Bonding; D008293:Malates / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008956:Models, Chemical; D011108:Polymers / Q000737:chemistry*; D011485:Protein Binding; D012542:Scattering, Radiation; D012965:Sodium Chloride / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013696:Temperature; D014867:Water / Q000737:chemistry*; D014965:X-Rays
chemical_list: D005782:Gels; D008293:Malates; D011108:Polymers; C121060:poly(malic acid); D014867:Water; D015060:1,2-Dipalmitoylphosphatidylcholine; D012965:Sodium Chloride