Lysozyme, myoglobin and BSA were used as models of globular proteins covering a wide range of pl. The purpose is to extend the studies to anionic lipid bilayers. Electrostatics is studied in cationic protein adsorptio...Lysozyme, myoglobin and BSA were used as models of globular proteins covering a wide range of pl. The purpose is to extend the studies to anionic lipid bilayers. Electrostatics is studied in cationic protein adsorption to zwitterionic PC and anionic mixed PC/PG SUVs. Protein adsorption is investigated in SUVs along with changes of fluorescence emission spectra. Partition coefficients and cooperativity parameters are calculated. At pl binding obtains maximum while at lower or higher pHs binding decreases. In Gouy-Chapman formalism activity coefficient goes with square charge, which deviations indicate asymmetric location of anionic phospholipid in the inner leaflet, in mixed SUVs for lysozyme- and myoglobin-PC/PG systems, in agreement with experiments and molecular dynamics simulations. Vesicles bind myoglobin anti-cooperatively while lysozyme-BSA cooperativitivey. A model is proposed for both, which composes two protein sub-layers with different structures and properties. Hill coefficient reflects subunit cooperativity of bi and tridomain proteins.展开更多
文摘Lysozyme, myoglobin and BSA were used as models of globular proteins covering a wide range of pl. The purpose is to extend the studies to anionic lipid bilayers. Electrostatics is studied in cationic protein adsorption to zwitterionic PC and anionic mixed PC/PG SUVs. Protein adsorption is investigated in SUVs along with changes of fluorescence emission spectra. Partition coefficients and cooperativity parameters are calculated. At pl binding obtains maximum while at lower or higher pHs binding decreases. In Gouy-Chapman formalism activity coefficient goes with square charge, which deviations indicate asymmetric location of anionic phospholipid in the inner leaflet, in mixed SUVs for lysozyme- and myoglobin-PC/PG systems, in agreement with experiments and molecular dynamics simulations. Vesicles bind myoglobin anti-cooperatively while lysozyme-BSA cooperativitivey. A model is proposed for both, which composes two protein sub-layers with different structures and properties. Hill coefficient reflects subunit cooperativity of bi and tridomain proteins.
