Carboxyacyl derivatives of cardiolipin as four-tailed hydrophobic anchors for the covalent coupling of hydrophilic proteins to liposomes.
Two carboxyacyl derivatives of cardiolipin, O-succinyl- and O-glutarylcardiolipin, were synthesized with the aim of using them as artificial membrane anchors for the immobilization of hydrophilic proteins to liposomes. Four adjacent fatty acid residues can be introduced into a protein with only one single amino group being blocked, by reacting the cardiolipin derivatives with the protein amino groups after carbodiimide activation. alpha-Chymotrypsin, used as a model protein, and modified with on average two molecules of O-succinylcardiolipin was incorporated into liposomes, which had been prepared by different methods, with very high yield. If incorporated in preformed liposomes, the carboxyacyl cardiolipin anchors were also efficient in binding proteins to liposomal surfaces. Up to 350 micrograms chymotrypsin/mumol lipid were coupled to small unilamellar vesicles, preserving reactivity of the enzyme towards specific macromolecular inhibitors. Human IgG could also be bound to anchor-containing liposomes with high protein to lipid coupling ratio as well as high coupling yield.
Niedermann
G
G
Institute of Biochemistry, Medical Faculty, Martin-Luther-University, Halle/Saale, Germany.
Weissig
V
V
Sternberg
B
B
Lasch
J
J
D000215:Acylation; D000818:Animals; D002308:Cardiolipins / Q000737:chemistry* / Q000648:ultrastructure; D002417:Cattle; D002918:Chymotrypsin / Q000737:chemistry / Q000378:metabolism; D005614:Freeze Fracturing; D006801:Humans; D007074:Immunoglobulin G; D007700:Kinetics; D008081:Liposomes; D008854:Microscopy, Electron; D011480:Protease Inhibitors / Q000737:chemistry / Q000494:pharmacology; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry*; D013329:Structure-Activity Relationship
D002308:Cardiolipins; D007074:Immunoglobulin G; D008081:Liposomes; D011480:Protease Inhibitors; D011506:Proteins; D002918:Chymotrypsin