Orientation of cecropin A helices in phospholipid bilayers determined by solid-state NMR spectroscopy. Biophys J 1999 Dec;77(6):3152-5
Date
12/10/1999Pubmed ID
10585936Pubmed Central ID
PMC1300585DOI
10.1016/S0006-3495(99)77145-6Scopus ID
2-s2.0-0032763732 (requires institutional sign-in at Scopus site) 81 CitationsAbstract
The orientation of the insect antibiotic peptide cecropin A (CecA) in the phospholipid bilayer membrane was determined using (15)N solid-state NMR spectroscopy. Two peptide samples, each specifically labeled with (15)N at Val(11) or Ala(27), were synthesized by solid phase techniques. The peptides were incorporated into phospholipid bilayers, prepared from a mixture of dimyristoylphosphatidylcholine and dimyristoylphosphatidylglycerol, and oriented on glass slides. The (15)N chemical shift solid-state NMR spectra from these uniaxially oriented samples display a single (15)N chemical shift frequency for each labeled residue. Both frequencies are near the upfield end of the (15)N chemical shift powder pattern, as expected for an alpha-helix with its long axis in the plane of the membrane and the NH bonds perpendicular to the direction of the magnetic field. These results support a mechanism of action in which CecA binds to and covers the membrane surface, thereby causing a general destabilization and leakiness of the lipid bilayer membrane. The data are discussed in relation to a proposed mechanism of membrane lysis and bacterial killing via an ion channel activity of CecA.
Author List
Marassi FM, Opella SJ, Juvvadi P, Merrifield RBAuthor
Francesca M. Marassi PhD Chair, Professor in the Biophysics department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Amino Acid SequenceAnimals
Anti-Infective Agents
Antimicrobial Cationic Peptides
Biophysical Phenomena
Biophysics
In Vitro Techniques
Insect Proteins
Lipid Bilayers
Magnetic Resonance Spectroscopy
Molecular Sequence Data
Peptides
Protein Structure, Secondary
