Effect of divalent cations on the structure of dipalmitoylphosphatidylcholine and phosphatidylcholine/phosphatidylglycerol bilayers: an 2H-NMR study.
The interactions of CaCl2 or MgCl2 with multilamellar phospholipid bilayers were studied by 2H-NMR. Two model membrane systems were used: (1) dipalmitoylphosphatidylcholine (DPPC) bilayers and (2) bilayers composed of a mixture of phosphatidylcholine and phosphatidylglycerol at a molar ratio of 5:1. Addition of 0.25 M CaCl2 to DPPC bilayers resulted in significant uniform increase of the order parameters of the lipid side chains; the effect of 0.25 M MgCl2 was insignificant. Both phosphatidylcholine and phosphatidylglycerol components of the mixed bilayers were affected by the presence of 0.25 M CaCl2 and, to a much smaller degree, by MgCl2. The addition of Ca2+ induced significantly larger increase of the order parameters of the phosphatidylcholine component. The results are consistent with the long-range effects of Ca2+ binding on the packing of the lipid membranes.
Zidovetzki
R
R
Department of Biology, University of California, Riverside 92521.
Atiya
A W
AW
De Boeck
H
H
D015060:1,2-Dipalmitoylphosphatidylcholine; D002118:Calcium / Q000494:pharmacology*; D002413:Cations, Divalent / Q000494:pharmacology; D003903:Deuterium; D008051:Lipid Bilayers; D008274:Magnesium / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008567:Membranes, Artificial; D008968:Molecular Conformation; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D011522:Protons
D002413:Cations, Divalent; D008051:Lipid Bilayers; D008567:Membranes, Artificial; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D011522:Protons; D015060:1,2-Dipalmitoylphosphatidylcholine; D003903:Deuterium; D008274:Magnesium; D002118:Calcium