Faculty Collaboration Database

Response of the headgroup of phosphatidylglycerol to membrane surface charge as studied by deuterium and phosphorus-31 nuclear magnetic resonance. Biochemistry 1991 Oct 29;30(43):10558-66

Date

10/29/1991

Pubmed ID

1931979

DOI

10.1021/bi00107a027

Scopus ID

2-s2.0-0026348313 (requires institutional sign-in at Scopus site)   36 Citations

Abstract

The response to membrane surface charge of the glycerol headgroup of dimyristoyl-phosphatidylglycerol (DMPG) was investigated via deuterium and phosphorus-31 nuclear magnetic resonance spectroscopy. The membrane surface charge was manipulated by adding various amounts of neutral dimyristoylphosphatidylcholine (DMPC) and/or positively charged didodecyldimethylammonium bromide (DDAB) to the negatively charged DMPG, selectively deuterated at the alpha and beta segments of its glycerol headgroup. The deuterium and phosphorus-31 nuclear magnetic resonance spectra were all characteristic of random dispersions of liquid-crystalline lipids in a bilayer configuration. Differential scanning calorimetry showed that all mixtures investigated exhibited gel to liquid-crystalline phase transitions below 35 degrees C. Measurements of the deuterium quadrupole splitting and of the phosphorus-31 chemical shift anisotropy lead to the following observations. (1) Dilution of the negative surface charge density by the addition of DMPC had little effect on the quadrupole splitting from either alpha- or beta-deuterated DMPG. (2) Direct cancellation of the negative surface charge density by addition of DDAB led to a progressive decrease in the quadrupole splitting measured from alpha-deuterated DMPG, while the quadrupole splitting measured from beta-deuterated DMPG increased. For alpha-deuterated DMPG addition of 0.3 mole fraction of DDAB resulted in the appearance of two distinct quadrupole splittings. No such effect was observed for beta-deuterated DMPG.

Author List

Marassi FM, Macdonald PM

Author

Francesca M. Marassi PhD Chair, Professor in the Biophysics department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Calorimetry, Differential Scanning
Deuterium
Dimyristoylphosphatidylcholine
Lipid Bilayers
Magnetic Resonance Spectroscopy
Membrane Potentials
Phosphatidylglycerols
Phosphorus Isotopes