Response of phosphatidylcholine in the gel and liquid-crystalline states to membrane surface charges

Journal Article · Tue Apr 09 00:00:00 EDT 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00228a029· OSTI ID:5509275

Macdonald, P M; Leisen, J; Marassi, F M ^[1]

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1. Univ. of Toronto, Ontario (Canada)

The influence of membrane surface charge on the conformation of the choline head group of 1,2-dimyristol-sn-glycero-3-phosphocholine (DMPC) was investigated in the gel and liquid-crystalline states by using {sup 2}H NMR spectroscopy of specifically choline-deuterated DMPC. The surface charge was made progressively more negative through admixture of various proportions of 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG). All membrane compositions showed nearly identical gel- to liquid-crystalline-phase transitions centered about 24C. The gel-state {sup 2}H NMR spectra from all three choline head-group deutero-labeling positions ({alpha}, {beta}, and {gamma}) decreased in intensity and broadened relative to the liquid-crystalline-state spectra. These effects were not so severe that they masked the overriding influence of surface charge on the choline head-group conformation as reflected in the {sup 2}H NMR spectra. These results demonstrate the utility of the {sup 2}H NMR approach for the investigation of surface charge effects in gel-state lipid membranes and indicate the potential for its exploitation in the study of other membrane-associated phenomena such as lipid lateral-phase segregation. In addition, the authors describe a model of the relationship between surface charge and {sup 2}H NMR quadrupole splittings which reproduces both qualitatively and quantitatively all the major features as established experimentally.

• OSTI ID: 5509275
• Journal Information: Biochemistry; (United States), Vol. 30:14; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CELL MEMBRANES
SURFACE PROPERTIES
PHOSPHOLIPIDS
NUCLEAR MAGNETIC RESONANCE
DEUTERIUM COMPOUNDS
PHASE STUDIES
CELL CONSTITUENTS
ESTERS
HYDROGEN COMPOUNDS
LIPIDS
MAGNETIC RESONANCE
MEMBRANES
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
RESONANCE
550601* - Medicine- Unsealed Radionuclides in Diagnostics