title: Kinetic and Structural Aspects of the Permeabilization of Biological and Model Membranes by Lichenysin.
abstract: The various lichenysins produced by Bacillus licheniformis are anionic surfactants with interesting properties. Here it is shown that lichenysin caused hemolysis of human erythrocytes, which varied with lichenysin concentration in a sigmoidal manner. The release of K(+) from red blood cells induced by lichenysin preceded the leakage of hemoglobin, and in addition, hemolysis could be impeded by the presence of compounds in the external medium having a size larger than that of PEG 3350, indicating a colloid-osmotic mechanism for hemolysis. Lichenysin also caused permeabilization of model phospholipid membranes, which was a slow process with an initial lag period of 10-20 s observed for all lichenysin concentrations. A high cholesterol ratio in the membrane decreased the extent of leakage as compared to that of pure POPC, whereas at lower ratios the effect of cholesterol was the opposite, enhancing the extent of leakage. POPE was found to decrease the extent of leakage at all the concentrations assayed, and inclusion of DPPC resulted in a considerable increase in CF leakage extent. From this scenario it was concluded that lipid membrane composition plays a role in the target membrane selectivity of lichenysin. Molecular dynamics simulations indicated that lichenysin is well distributed along the bilayer, and Na(+) ions can penetrate inside the bilayer through the lichenysin molecules. The presence of lichenysin in the membrane increases the permeability of the membrane to hydrophilic molecules facilitating its flux across the lipid palisade. The results presented in this work contribute to understanding the molecular mechanisms that explain the biological actions of lichenysin related to biomembranes.
authors.affiliation: Laboratorio de Microbiología, Facultad de Farmacia, Universidad de Barcelona , Joan XXIII s/n, E-08028 Barcelona, Spain.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Coronel
authors.affiliation: Departamento de Bioquímica y Biología Molecular-A, Facultad de Veterinaria, Universidad de Murcia , E-30100 Murcia, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Aranda
authors.affiliation: Departamento de Bioquímica y Biología Molecular-A, Facultad de Veterinaria, Universidad de Murcia , E-30100 Murcia, Spain.
authors.forename: José A
authors.initials: JA
authors.lastname: Teruel
authors.affiliation: Laboratorio de Microbiología, Facultad de Farmacia, Universidad de Barcelona , Joan XXIII s/n, E-08028 Barcelona, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Marqués
authors.affiliation: Laboratorio de Microbiología, Facultad de Farmacia, Universidad de Barcelona , Joan XXIII s/n, E-08028 Barcelona, Spain.
authors.forename: Ángeles
authors.initials: Á
authors.lastname: Manresa
authors.affiliation: Departamento de Bioquímica y Biología Molecular-A, Facultad de Veterinaria, Universidad de Murcia , E-30100 Murcia, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Ortiz
mesh_terms: D004912:Erythrocytes / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry; D008074:Lipoproteins / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D010539:Permeability; D010714:Phosphatidylethanolamines / Q000737:chemistry; D013501:Surface-Active Agents / Q000009:adverse effects / Q000737:chemistry
chemical_list: D008051:Lipid Bilayers; D008074:Lipoproteins; D010714:Phosphatidylethanolamines; D013501:Surface-Active Agents; C057561:1-palmitoyl-2-oleoylphosphatidylethanolamine