Secondary Structure and Lipid Contact of a Peptide Antibiotic in Phospholipid Bilayers by REDOR
The chemical shifts of specific 13C and 15N labels distributed throughout KIAGKIA-KIAGKIA-KIAGKIA (K3), an amphiphilic 21-residue antimicrobial peptide, prove that the peptide is in an all α-helical conformation in the bilayers of multilamellar vesicles (MLVs) containing dipalmitoylphosphatidylcholi...
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Published in | Biophysical journal Vol. 87; no. 1; pp. 662 - 674 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Elsevier Inc
01.07.2004
Biophysical Society |
Subjects | |
Online Access | Get full text |
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Summary: | The chemical shifts of specific
13C and
15N labels distributed throughout KIAGKIA-KIAGKIA-KIAGKIA (K3), an amphiphilic 21-residue antimicrobial peptide, prove that the peptide is in an all
α-helical conformation in the bilayers of multilamellar vesicles (MLVs) containing dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylglycerol (1:1). Rotational-echo double-resonance (REDOR)
13C{
31P} and
15N{
31P} experiments on the same labeled MLVs show that on partitioning into the bilayer, the peptide chains remain in contact with lipid headgroups. The amphipathic lysine side chains of K3 in particular appear to play a key role in the electrostatic interactions with the acidic lipid headgroups. In addition to the extensive peptide-headgroup contact,
13C{
19F} REDOR experiments on MLVs containing specifically
19F-labeled lipid tails suggest that a portion of the peptide is surrounded by a large number of lipid acyl chains. Complementary
31P{
19F} REDOR experiments on these MLVs show an enhanced headgroup-lipid tail contact resulting from the presence of K3. Despite these distortions, static
31P NMR lineshapes indicate that the lamellar structure of the membrane is preserved. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Address reprint requests to Jacob Schaefer, Dept. of Chemistry, Washington University, 1 Brookings Dr., St. Louis, MO 63130. Tel.: 314-935-6844; Fax: 314-935-4481; E-mail: schaefer@wuchem.wustl.edu |
ISSN: | 0006-3495 1542-0086 |
DOI: | 10.1529/biophysj.103.032706 |