1: Biophys Chem  1985 Mar;21(3-4):277-84 

Interaction between Ca2+ and dipalmitoylphosphatidylcholine membranes. II.
Fluorescence anisotropy study.

Kataoka R, Aruga S, Mitaku S, Kinosita K Jr, Ikegami A.

The effect of Ca2+ on the molecular mobility in dipalmitoylphosphatidylcholine
membranes was studied by steady-state and time-resolved measurements of
fluorescence anisotropy. The fluorescence anisotropy decay of
1,6-diphenyl-1,3,5-hexatriene in the hydrocarbon region indicated that the free
volume of molecular rotation became more restricted when the Ca2+ concentration
was increased. The decrease of the molecular mobility was observed from 1 mM
Ca2+, at which the number of bound Ca2+ is much less than that of the total
lipid molecules. A distinct difference between Ca2+ and Mg2+ effects suggested
that the change in various membrane properties was induced by the binding of
these ions. From these results we propose a long-range attractive interaction
between bound Ca2+ and the polar head groups of distant phosphatidylcholine
molecules.

PMID: 3838686 [PubMed - indexed for MEDLINE]