Lipid-polypeptide interactions in bilayer lipid membranes

摘要: The modifications of the electrical properties bilayer lipid membranes (BLM) composed cholesterol and an ionic surfactant upon interaction with charged polypeptides were studied. addition 10−8m polylysine (Ps+) to one side anionic dodecylphosphate BLM increases specific membrane conductance over 1000-fold (from 10−8 10−5 mho/cm2) develops a cationic transmembrane potential larger than 50 mV. This is reverted by polyanions such as RNA, polyglutamic or polyadenilic acid same on which Ps+ present, opposite side, trypsin either side. Both changes are hindered increasing strength raising pH bathing medium, disappearing above 11.5 where it known that folds into α-helix. (PGA) cholesterol-hexadecyltrimethylammonium bromide results in increased development polycations aqueous phase PGA present. Addition both sides neutral 7-dehydrocholesterol induces no significant change. observations suggest formation polymer resultant from interaction, predominantly electrostatic, isolated components. implications these discussed terms current models structure.