Deuterium nuclear magnetic resonance spectroscopic study of the fluorescent probe diphenylhexatriene in model membrane systems

Journal Article · Tue Oct 21 00:00:00 EDT 1986 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00369a027· OSTI ID:6796758

Kintanar, A; Kunwar, A C; Oldfield, E

We have investigated the deuterium (/sup 2/H) nuclear magnetic resonance (NMR) spectra of two /sup 2/H-labeled fluorescence probes (trans,trans,trans-1,6-diphenylhexa-1,3,5-trienes, DPHs) incorporated into model lipid bilayer membrane systems at various temperatures. The membranes consisted of multilamellar bilayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) containing varying concentrations of cholesterol. The conventional one-order parameter approach often used in the analysis of the NMR data of lipid membranes does not explain the observed temperature variations of the spectral features. Consistent with the molecular symmetry, the results have thus been analyzed in terms of an ordering matrix with more than one independent element. The molecular order parameter (SNMR), the order along the long molecular axis, in the pure lipid system varies from 0.49 to 0.26 as the temperature is increased from 25 to 57 degrees C. These values are somewhat larger than the order parameters obtained from fluorescence depolarization (SFLU) on sonicated DMPC vesicles. Such discrepancies probably arise from the looser packing of the sonicated vesicles. Addition of cholesterol to the model membranes causes the order parameter of the probe molecules to increase. At 35 degrees C, SNMR increases from 0.38 (with no cholesterol) to 0.92 (in the presence of 50 mol % cholesterol). These values are about 10% larger than those obtained from fluorescence depolarization studies on sonicated vesicles. The SNMR for DPH are somewhat larger than those obtained in earlier NMR studies of /sup 2/H-labeled cholesterol. However, they compare well with those obtained for /sup 2/H-labeled DMPC.

• Research Organization: Univ. of Illinois at Urbana-Champaign
• OSTI ID: 6796758
• Journal Information: Biochemistry; (United States), Vol. 21
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
59 BASIC BIOLOGICAL SCIENCES
CELL MEMBRANES
MOLECULAR STRUCTURE
BIOLOGICAL MODELS
CHOLESTEROL
DEUTERIUM
FLUORESCENCE
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
PHOSPHOLIPIDS
POLYENES
TRACER TECHNIQUES
CELL CONSTITUENTS
ESTERS
HYDROCARBONS
HYDROGEN ISOTOPES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LIPIDS
LUMINESCENCE
MAGNETIC RESONANCE
MEMBRANES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
RESONANCE
SPECTRA
STABLE ISOTOPES
STEROIDS
STEROLS
550600* - Medicine
550201 - Biochemistry- Tracer Techniques