title: Interactions of calcium binding proteins, parvalbumin and alpha-lactalbumin, with dipalmitoylphosphatidylcholine vesicles.
abstract: Interactions of Ca2+ binding proteins, pike (Esox lucius) parvalbumins pI 4.2 and 5.0, and bovine and human alpha-lactalbumins, with dipalmitoylphosphatidylcholine vesicles were studied by means of scanning microcalorimetry and intrinsic tyrosine and tryptophan fluorescence methods. The interactions of pike parvalbumins are modulated by Ca2+ and Mg2+ binding to the protein and induce some changes in the physical properties of both the proteins and liposomes. Liposomes increased thermal stability of Ca2+-loaded parvalbumin and decreased thermal stability of both Mg2+-loaded and metal-free protein. The interaction of parvalbumin with liposomes affects the phase transition from gel to liquid-crystalline state in liposomes. Ca2+-loaded alpha-lactalbumin interacts with liposomes in its native state while the metal-free protein binds to the liposomes mainly in its thermally denatured state. The results of the microcalorimetric and spectrofluorometric studies are supported by data obtained by means of gel-chromatography on Sepharose 4B. It may be suggested that these metal-modulated interactions of Ca2+-binding proteins with membranes have some functional significance.
authors.affiliation: Institute of Biological Physics, Academy of Sciences of the USSR, Pushchino.
authors.forename: E A
authors.initials: EA
authors.lastname: Permyakov
authors.forename: D I
authors.initials: DI
authors.lastname: Kreimer
authors.forename: L P
authors.initials: LP
authors.lastname: Kalinichenko
authors.forename: V L
authors.initials: VL
authors.lastname: Shnyrov
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002151:Calorimetry; D002417:Cattle; D006801:Humans; D007768:Lactalbumin / Q000378:metabolism*; D008051:Lipid Bilayers; D008274:Magnesium / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism*; D010320:Parvalbumins / Q000378:metabolism*; D011485:Protein Binding; D012487:Salmonidae
chemical_list: D002135:Calcium-Binding Proteins; D008051:Lipid Bilayers; D009124:Muscle Proteins; D010320:Parvalbumins; D015060:1,2-Dipalmitoylphosphatidylcholine; D007768:Lactalbumin; D008274:Magnesium; D002118:Calcium