Two-dimensional 1H NMR experiments show that the 23-residue magainin antibiotic peptide is an alpha-helix in dodecylphosphocholine micelles, sodium dodecylsulfate micelles, and trifluoroethanol/water solution.
Magainin2 is a 23-residue antibiotic peptide that disrupts the ionic gradient across certain cell membranes. Two-dimensional 1H NMR spectroscopy was used to investigate the structure of the peptide in three of the membrane environments most commonly employed in biophysical studies. Sequence-specific resonance assignments were determined for the peptide in perdeuterated dodecylphosphocholine (DPC) and sodium dodecylsulfate micelles and confirmed for the peptide in 2,2,2-trifluoroethanol solution. The secondary structure is shown to be helical in all of the solvent systems. The NMR data were used as a set of restraints for a simulated annealing protocol that generated a family of three-dimensional structures of the peptide in DPC micelles, which superimposed best between residues 4 and 20. For these residues, the mean pairwise rms difference for the backbone atoms is 0.47 +/- 0.10 A from the average structure. The calculated peptide structures appear to be curved, with the bend centered at residues Phe12 and Gly13.
Gesell
J
J
Department of Chemistry, University of Pennsylvania, PA 19104, USA.
Zasloff
M
M
Opella
S J
SJ
D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000737:chemistry*; D023181:Antimicrobial Cationic Peptides; D003903:Deuterium; D006859:Hydrogen; D054806:Magainins; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008823:Micelles; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D010767:Phosphorylcholine / Q000031:analogs & derivatives; D017433:Protein Structure, Secondary; D012967:Sodium Dodecyl Sulfate; D012996:Solutions; D014270:Trifluoroethanol; D014867:Water; D029867:Xenopus Proteins
D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D054806:Magainins; D008823:Micelles; D010455:Peptides; D012996:Solutions; D029867:Xenopus Proteins; D014867:Water; D010767:Phosphorylcholine; C053301:magainin 2 peptide, Xenopus; D012967:Sodium Dodecyl Sulfate; C028810:dodecylphosphocholine; D014270:Trifluoroethanol; D006859:Hydrogen; D003903:Deuterium