Covalent linkage of a synthetic peptide to a fluorescent phospholipid and its incorporation into supported phospholipid monolayers.
A number of fluorescent peptide-lipid conjugates have been synthesized. Peptides with ten or eleven amino acids are linked through a single lysine residue to the headgroup of phosphatidylethanolamine, fluorescently labelled on one acyl chain, using homobifunctional disuccinimidyl crosslinking reagents. Peptide-lipids can be further derivatized with the hapten dinitrophenyl. Purified peptide-lipids have been incorporated into dimyristoylphosphatidylcholine monolayers at the interface of air and phosphate-buffered saline, at concentrations of up to 11 mol%. For equal average molecular areas, monolayers containing peptide-lipids have higher surface pressures than pure lipid monolayers; for equal surface pressures, peptide-lipid monolayers have higher average molecular areas than pure lipid monolayers. When the peptide-lipid monolayers are transferred to hydrophobic glass slides, the fluorescence appears uniformly distributed. Fluorescence recovery after photobleaching measurements indicate that peptide-lipids diffuse in the monolayer with coefficient 1.5 X 10(-9) cm2/s, which is much smaller than that of typical lipids in fluid membranes. In addition, the diffusion coefficient of peptide-lipids decreases with increasing peptide-lipid concentration. We conclude that the peptide portion of the peptide-lipid associates with the lipid monolayer and/or that peptide-lipids oligomerize.
D009327:4-Chloro-7-nitrobenzofurazan / Q000031:analogs & derivatives / Q000378:metabolism*; D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000276:immunology; D004058:Diffusion; D004134:Dimyristoylphosphatidylcholine; D004139:Dinitrofluorobenzene / Q000378:metabolism; D007074:Immunoglobulin G / Q000378:metabolism; D008567:Membranes, Artificial; D008856:Microscopy, Fluorescence; D009842:Oligopeptides / Q000378:metabolism*; D010069:Oxadiazoles / Q000378:metabolism*; D010714:Phosphatidylethanolamines / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D013388:Succinimides / Q000378:metabolism
D007074:Immunoglobulin G; D008567:Membranes, Artificial; D009842:Oligopeptides; D010069:Oxadiazoles; D010714:Phosphatidylethanolamines; D013388:Succinimides; C027509:renin inhibitory peptide; D004139:Dinitrofluorobenzene; D009327:4-Chloro-7-nitrobenzofurazan; D004134:Dimyristoylphosphatidylcholine