Orientation of Cecropin A Helices in Phospholipid Bilayers Determined by Solid-State NMR Spectroscopy
| Autor: | Stanley J. Opella, R. B. Merrifield, Francesca M. Marassi, Padmaja Juvvadi |
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| Rok vydání: | 1999 |
| Předmět: |
Magnetic Resonance Spectroscopy
Lipid Bilayers Molecular Sequence Data Biophysics Analytical chemistry Phospholipid Peptide In Vitro Techniques 010402 general chemistry 01 natural sciences Biophysical Phenomena Protein Structure Secondary 03 medical and health sciences chemistry.chemical_compound Anti-Infective Agents Animals Amino Acid Sequence Spectroscopy Lipid bilayer 030304 developmental biology chemistry.chemical_classification 0303 health sciences Chemistry Nuclear magnetic resonance spectroscopy 0104 chemical sciences NMR spectra database Crystallography Membrane Solid-state nuclear magnetic resonance Insect Proteins Peptides Antimicrobial Cationic Peptides Research Article |
| Zdroj: | Biophysical Journal. 77:3152-3155 |
| ISSN: | 0006-3495 |
| DOI: | 10.1016/s0006-3495(99)77145-6 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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