title: The insertion of the antimicrobial peptide dicynthaurin monomer in model membranes: thermodynamics and structural characterization.
abstract: This paper is focused on the thermodynamics and the structural investigation of the interaction of the antimicrobial peptide dicynthaurin monomer with model lipid membranes composed of mixtures of 1-palmitoyl-2-oleyl-glycerophosphocholine and -glycerophosphoglycerol. The thermodynamic binding parameters as obtained by isothermal titration calorimetry reveal strong binding toward the lipid model system dominated by large chemical binding constants which exceeds the electrostatic binding effects and thus suggests insertion of the amphipathic alpha-helical peptide into the hydrophobic membrane core. Circular dichroism study shows that the peptide exhibits trans-membrane alpha-helix secondary structure. Neutron diffraction measurements using partially deuterated sequences were successfully applied to determine the orientation of the peptide thus proving insertion into the hydrophobic membrane core. This insertion and the formation of higher order porelike aggregates is assumed to be the most relevant event in microbial membrane perturbation that in vivo finally leads to bacterial cell death on a fast time scale.
authors: Institute of Medical Physics & Biophysics, University of Leipzig, 04107 Leipzig, Germany. bringezu@denet.de
authors: Frank
authors: F
authors: Bringezu
authors: Shaoying
authors: S
authors: Wen
authors: Silvia
authors: S
authors: Dante
authors: Thomas
authors: T
authors: Hauss
authors: Monika
authors: M
authors: Majerowicz
authors: Alan
authors: A
authors: Waring
mesh_terms: D002151:Calorimetry; D002942:Circular Dichroism; D008563:Membrane Lipids / Q000737:chemistry; D008567:Membranes, Artificial; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry; D010715:Phosphatidylglycerols / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D008563:Membrane Lipids; D008567:Membranes, Artificial; D010455:Peptides; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; C437228:dicynthaurin; C060037:1-palmitoyl-2-oleoylglycero-3-phosphoglycerol; C028694:1-palmitoyl-2-oleoylphosphatidylcholine