title: Conformational and membrane interaction studies of the antimicrobial peptide alyteserin-1c and its analogue [E4K]alyteserin-1c.
abstract: Alyteserin-1c (GLKEIFKAGLGSLVKGIAAHVAS.NH(2)), first isolated from skin secretions of the midwife toad Alytes obstetricans, shows selective growth-inhibitory activity against Gram-negative bacteria. The structures of alyteserin-1c and its more potent and less haemolytic analogue [E4K]alyteserin-1c were investigated in various solution and membrane mimicking environments by proton NMR spectroscopy and molecular modelling. In aqueous solution, the peptide displays a lack of secondary structure but, in a 2,2,2-trifluoroethanol (TFE-d(3))-H(2)O solvent mixture, the structure is characterised by an extended alpha helix between residues Leu(2) and Val(21). Solution structural studies in the membrane mimicking environments, sodium dodecyl sulphate (SDS), dodecylphosphocholine (DPC), and 1,2-dihexanoyl-sn-glycero-3-phosphatidylcholine (DHPC) micelles, indicate that these peptides display an alpha helical structure between residues Lys(3) and Val(21). Positional studies of the peptides in SDS, DPC and DHPC media show that the N-terminal and central residues lie inside the micelle while C-terminal residues beyond Ala(19) do not interact with the micelles.
authors.affiliation: UCD School of Biomolecular and Biomedical Science, UCD Centre for Synthesis and Chemical Biology, UCD Conway institute, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Anusha P
authors.initials: AP
authors.lastname: Subasinghage
authors.forename: Donal
authors.initials: D
authors.lastname: O'Flynn
authors.forename: J Michael
authors.initials: JM
authors.lastname: Conlon
authors.forename: Chandralal M
authors.initials: CM
authors.lastname: Hewage
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry* / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry* / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development; D002712:Chlorides / Q000737:chemistry; D003497:Cyclic N-Oxides / Q000737:chemistry; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D008239:Lysine; D017895:Manganese Compounds / Q000737:chemistry; D008563:Membrane Lipids / Q000737:chemistry*; D008567:Membranes, Artificial; D008823:Micelles; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D010742:Phospholipid Ethers / Q000737:chemistry; D010767:Phosphorylcholine / Q000031:analogs & derivatives / Q000737:chemistry; D011487:Protein Conformation; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013113:Spin Labels; D013329:Structure-Activity Relationship; D014270:Trifluoroethanol / Q000737:chemistry; D014633:Valine; D014867:Water / Q000737:chemistry
chemical_list: C052298:1,2-dihexadecyl-sn-glycero-3-phosphocholine; D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D002712:Chlorides; D003497:Cyclic N-Oxides; D017895:Manganese Compounds; D008563:Membrane Lipids; D008567:Membranes, Artificial; D008823:Micelles; D010742:Phospholipid Ethers; D012997:Solvents; D013113:Spin Labels; C555397:alyteserin 1c, Alytes obstetricans; D014867:Water; D010767:Phosphorylcholine; C005072:5-doxylstearic acid; D012967:Sodium Dodecyl Sulfate; C032363:16-nitroxystearic acid; C028810:dodecylphosphocholine; D014270:Trifluoroethanol; D014633:Valine; D008239:Lysine; C025340:manganese chloride