title: The influence of rough lipopolysaccharide structure on molecular interactions with mammalian antimicrobial peptides.
abstract: The influence of Escherichia coli rough lipopolysaccharide chemotype on the membrane activity of the mammalian antimicrobial peptides (AMPs) human cathelicidin (LL37) and bovine lactoferricin (LFb) was studied on bilayers using solid state (2)H NMR (ssNMR) and on monolayers using the subphase injection technique, Brewster angle microscopy (BAM) and neutron reflectivity (NR). The two AMPs were selected because of their differing biological activities. Chain-deuterated dipalmitoylphosphatidylcholine (d62-DPPC) was added to the LPS samples, to highlight alterations in the system properties caused by the presence of the different LPS chemotypes and upon AMP challenge. Both LPS chemotypes showed a temperature dependent influence on the packing of the DPPC molecules, with a fluidizing effect exerted below the DPPC phase transition temperature (Tm), and an ordering effect observed above the Tm. The magnitude of these effects was influenced by LPS structure; the shorter Rc LPS promoted more ordered lipid packing compared to the longer Ra LPS. These differential ordering effects in turn influenced the penetrative activity of the two peptides, as the perturbation induced by both AMPs to Ra LPS-containing models was greater than that observed in those containing Rc LPS. The NR data suggests that in addition to penetrating into the monolayers, both LL37 and LFb formed a non-interacting layer below the LPS/DPPC monolayer. The overall activity of LL37, which showed a deeper penetration into the model membranes, was more marked than that of LFb, which appeared to localise at the interfacial region, thus providing evidence for the molecular origins of their different biological activities.
authors.affiliation: Institute of Pharmaceutical Science, King's College London, 150 Stamford Street, London SE1 9NH, UK; Department of Nanobiotechnology, University of Natural Resources and Life Science, Muthgasse 11/II, Vienna 1190, Austria.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Bello
authors.affiliation: Laboratoire Réactions et Génie des Procédés, UMR-7274, Plateforme SVS, 13 Rue du Bois de la Champelle, 54500 Vandœuvre-lés-Nancy, France.
authors.forename: Alice
authors.initials: A
authors.lastname: Bodin
authors.affiliation: Institute of Pharmaceutical Science, King's College London, 150 Stamford Street, London SE1 9NH, UK.
authors.forename: M Jayne
authors.initials: MJ
authors.lastname: Lawrence
authors.affiliation: Institute of Pharmaceutical Science, King's College London, 150 Stamford Street, London SE1 9NH, UK.
authors.forename: David
authors.initials: D
authors.lastname: Barlow
authors.affiliation: Institute of Pharmaceutical Science, King's College London, 150 Stamford Street, London SE1 9NH, UK.
authors.forename: A James
authors.initials: AJ
authors.lastname: Mason
authors.affiliation: Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble, France. Electronic address: barker@ill.eu.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Barker
authors.affiliation: Institute of Pharmaceutical Science, King's College London, 150 Stamford Street, London SE1 9NH, UK. Electronic address: richard.d.harvey@kcl.ac.uk.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Harvey
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D000818:Animals; D023181:Antimicrobial Cationic Peptides; D054804:Cathelicidins / Q000737:chemistry*; D002417:Cattle; D004926:Escherichia coli / Q000737:chemistry*; D006801:Humans; D007781:Lactoferrin / Q000737:chemistry*; D008070:Lipopolysaccharides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure
chemical_list: D023181:Antimicrobial Cationic Peptides; D054804:Cathelicidins; D008070:Lipopolysaccharides; D015060:1,2-Dipalmitoylphosphatidylcholine; D007781:Lactoferrin
keywords: Air/liquid interface; Antimicrobial peptides; Bilayer; Endotoxin; LPS; Lipopolysaccharide; Monolayer; Neutron reflectivity; ssNMR