Interactions of parvalbumins with model phospholipid vesicles.

Interactions of Ca2+-binding proteins, parvalbumins, with model vesicles formed with both synthetic (dipalmitoylphosphatidylcholine) and natural (phosphatidylcholine and phosphatidylethanolamine) phospholipids have been revealed and studied by means of gel-chromatography, electron microscopy, intrinsic fluorescence and microcalorimetry methods. There are at least two populations of liposome-bound parvalbumin one of which has higher affinity to the liposomes (effective binding constant about 10(6) M-1) than the other one. The interaction is modulated by Ca2+ and Mg2+ ions and induces changes in properties of both parvalbumin and liposomes.