Interaction of the water-soluble protein aprotinin with liposomes: gel-filtration, turbidity studies, and 31P NMR studies.
The interactions of a water-soluble nonmembrane protein aprotinin with multilamellar vesicles (MLV) and small unilamellar vesicles (SUV) from soybean phospholipids were studied using Sephadex G-75 gel chromatography combined with different methods of the analysis of the eluate fractions (fluorescence, light-scattering, turbidity; 31P NMR spectroscopy). The composition of the liposomes mainly containing soybean phosphatidylcholine (PC) was varied by the addition of phosphatidylethanolamine (PE), phosphatidylinositol (PI) and lyso-phosphatidylcholine (lyso-PC). To evaluate the lipid-protein interactions, the amount of aprotinin in the MLV-aprotinin complexes was determined. Lipid-protein interactions were found to strongly depend on the liposome composition, medium pH and ionic strength. These dependencies point to the electrostatic nature of the aprotinin-lipid interactions. 31P NMR spectroscopy of the MLV-aprotinin complexes indicated that aprotinin influences the phospholipid structure in MLV at pH 3.0. In the case of PC:PE:PI and PC:PE:PI:lyso-PC vesicles, aprotinin induced liposome aggregation and a lamellar-to-isotropic phase transition of the phospholipids.
Tiourina
O
O
Department of Chemical Enzymology, Faculty of Chemistry, Lomonosov Moscow State University, Moscow, Russia.
Sharf
T
T
Balkina
A
A
Ollivon
M
M
Selischeva
A
A
Sorokoumova
G
G
Larionova
N
N
D007611:Aprotinin / Q000737:chemistry / Q000378:metabolism*; D002850:Chromatography, Gel; D006863:Hydrogen-Ion Concentration; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009391:Nephelometry and Turbidimetry / Q000379:methods*; D010713:Phosphatidylcholines / Q000737:chemistry; D010714:Phosphatidylethanolamines / Q000737:chemistry; D010716:Phosphatidylinositols / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D012965:Sodium Chloride / Q000737:chemistry; D012995:Solubility; D013025:Glycine max / Q000737:chemistry; D014867:Water / Q000737:chemistry
D008055:Lipids; D008081:Liposomes; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010716:Phosphatidylinositols; D010743:Phospholipids; D014867:Water; D012965:Sodium Chloride; D007611:Aprotinin