sup 31 P and sup 2 H NMR studies of structure and motion in bilayers of phosphatidylcholine and phosphatidylethanolamine

Journal Article · Tue Oct 04 00:00:00 EDT 1988 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00420a025· OSTI ID:6896449

Ghosh, R ^[1]

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1. Biocentre, Basel (Switzerland)

The structural and motional properties of mixed bilayers of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) have been examined by using wide-line {sup 31}P, {sup 14}N, and {sup 2H} NMR. {sup 2}H and {sup 14}N NMR data showed that in mixed bilayers containing both PC and PE the conformations of the head-group moieties are essentially identical with those observed for bilayers containing a single phospholipid species. Equimolar amounts of cholesterol induce also only a small change in head-group conformation. For all phospholipid mixtures studied, the {sup 31}P T{sub 1} relaxation was homogeneous over the whole powder spectrum and could be fitted to a single-exponential decay. The {sup 31}P vs temperature profiles were analyzed by a simple correlation model. The presence of equimolar amounts of PE containing either the same (POPE) or a different (Escherichia coli PE) fatty acid composition had essentially no effect on the rate of rotational diffusion of the phosphate groups, with the correlation time being found to be 0.68 ns at 20{degree}C. The presence of equimolar amounts of cholesterol decreased the correlation time to 0.65 ns, and also the activation energy was reduced to 22.6 kJ mol{sup {minus}1}. The authors interpret the decrease in activation energy as being due to the spacing effect of cholesterol which reduces the H-bonding interactions between head-groups, allowing them to rotate more freely. For all cases examined, the rotational diffusion of the phosphate moieties was slower than that observed for the rigid glycerol backbone of the molecule, the latter probably corresponding to overall phospholipid rotation.

• OSTI ID: 6896449
• Journal Information: Biochemistry; (USA), Vol. 27:20; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
MEMBRANES
PHASE STUDIES
PHOSPHOLIPIDS
NUCLEAR MAGNETIC RESONANCE
AMINES
ANISOTROPY
CHOLINE
DEUTERIUM COMPOUNDS
MOLECULAR STRUCTURE
NITROGEN 14
NMR SPECTRA
PHOSPHORUS 31
RELAXATION TIME
STOICHIOMETRY
STRUCTURE-ACTIVITY RELATIONSHIPS
TEMPERATURE DEPENDENCE
ALCOHOLS
AMMONIUM COMPOUNDS
DRUGS
ESTERS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPES
LIGHT NUCLEI
LIPIDS
LIPOTROPIC FACTORS
MAGNETIC RESONANCE
NITROGEN ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
QUATERNARY COMPOUNDS
RESONANCE
SPECTRA
STABLE ISOTOPES
550601* - Medicine- Unsealed Radionuclides in Diagnostics