Document Detail

A deuterium NMR study of labelled n-alkanol anesthetics in a model membrane.
MedLine Citation:
PMID:  3753904     Owner:  NLM     Status:  MEDLINE    
The 2H-NMR spectra of 50 wt.% aqueous multilamellar dispersions of dipalmitoylphosphatidylcholine (DPPC) containing either selectively deuterated 1-decanol (25 mol%) or [2H17]-1-octanol (25 mol%) have been measured as a function of temperature. Both alkanols are potent anesthetics. A detailed carbon-deuterium bond order parameter profile of 1-decanol in liquid crystalline phospholipid dispersions at 50 degrees C was determined from the quadrupolar splittings of 1-decanols deuterated at eight different positions. A maximum order parameter SCD = 0.20 was obtained for [5,5-2H2]-1-decanol, with labels at both ends of the 1-decanol exhibiting reduced order parameters. Explanations for the reduced order towards the hydroxyl group of 1-decanol are discussed in terms of either increased amplitudes of motion or geometric effects due to hydrogen bonding. By comparing the order parameter profile of sn-2 chain deuterated phosphatidylcholine dispersions containing 25 mol% 1-decanol (J.L. Thewalt, S.R. Wassall, H. Gorrissen and R.J. Cushley, Biochim. Biophys. Acta, 817 (1985) 355) with the profile of deuterated 1-decanol in DPPC, we estimate that decanol is approximately parallel to the C-3 to C-13 region of the phosphatidylcholine's sn-2 chain. Variation of the spectral moments M1 with temperature indicates that both 1-decanol and 1-octanol are sensitive to the packing of the lipid in which they are dissolved. Below the phase transition temperature, the 2H-NMR spectra of either 1-decanol (selectively deuterated) or 1-octanol (perdeuterated) are broad powder patterns, characteristic of axially symmetric rotation about the alcohol's long axis. This is in contrast to the 2H-NMR spectra obtained from deuterated phosphatidylcholine under similar conditions, which implies that the phospholipid acyl chain conformations are more restricted than those of the alcohol at these temperatures. From the M1 behavior of the various alkanol chain segments with temperature, the gel to liquid crystalline phase transition is seen to initiate in the middle of the DPPC/1-alkanol bilayer.
J L Thewalt; A P Tulloch; R J Cushley
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Chemistry and physics of lipids     Volume:  39     ISSN:  0009-3084     ISO Abbreviation:  Chem. Phys. Lipids     Publication Date:  1986 Jan 
Date Detail:
Created Date:  1986-04-04     Completed Date:  1986-04-04     Revised Date:  2000-12-18    
Medline Journal Info:
Nlm Unique ID:  0067206     Medline TA:  Chem Phys Lipids     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  93-107     Citation Subset:  IM    
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MeSH Terms
Fatty Alcohols*
Lipid Bilayers*
Magnetic Resonance Spectroscopy / methods
Models, Biological
Pulmonary Surfactants*
Reg. No./Substance:
0/Anesthetics; 0/Fatty Alcohols; 0/Lipid Bilayers; 0/Pulmonary Surfactants; 112-30-1/n-decyl alcohol; 7782-39-0/Deuterium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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