Evidence for dimer formation by an amphiphilic heptapeptide that mediates chloride and carboxyfluorescein release from liposomes.
Heptapeptides having dioctadecyl, N-terminal hydrocarbon chains insert in phospholipid bilayer membranes and form pores through which at least chloride ions pass. Although amphiphilic, these compounds do not typically form vesicles themselves. They insert in the bilayers of phospholipid vesicles and mediate the release of carboxyfluorescein. Hill analysis indicates that at least two molecules of the amphiphile are involved in pore formation. In CD2Cl2, dimer formation is detected by NMR chemical shift changes. The anion release activity of individual anion transporters is increased by linking them covalently at the C-terminus or, even more, by linking them at the N-terminus. Evidence is presented that either linked molecule releases chloride from liposomes more effectively and rapidly than the individual transporter molecule at a comparable concentration.
Pajewski
Robert
R
Department of Molecular Biology & Pharmacology, Washington University School of Mediine, St. Louis, MO 63110, USA.
Ferdani
Riccardo
R
Pajewska
Jolanta
J
Djedovic
Natasha
N
Schlesinger
Paul H
PH
Gokel
George W
GW
D000588:Amines / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry*; D019281:Dimerization; D005452:Fluoresceins / Q000737:chemistry*; D007700:Kinetics; D008081:Liposomes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry*; D013501:Surface-Active Agents / Q000138:chemical synthesis / Q000737:chemistry*
D000588:Amines; D002712:Chlorides; D005452:Fluoresceins; D008081:Liposomes; D009842:Oligopeptides; D013501:Surface-Active Agents; C095819:dioctadecylamine; C024098:6-carboxyfluorescein