Solid-phase synthesis and application of double-fluorescent-labeled lipopeptides, containing a CTL-epitope from the measles fusion protein

Publication Type:

Journal Article

Source:

Journal of Peptide Research, Volume 54, Number 5, pp. 436-443 (1999)

ISBN:

1397-002X

Keywords:

confocal microscopy; cytotoxic t lymphocyte; fluorescein; fluorescence; lipopeptide; solid-phase peptide; synthesis; tetramethylrhodamine; cytotoxic t-lymphocytes; outer-membrane protein; cyclic-peptides; vaccine; efficiency; induction; lysine; cells

Abstract:

The mechanism which enables lipopeptides to induce cytotoxicity is not known. By preparing fluorescent-labeled lipopeptides one might unravel the mechanism of their entry into the cell and their intracellular pathway. A method of preparing double-fluorescent-labeled peptides by solid-phase chemistry is described. As model peptides we have chosen analogs of the sequence RRYPDAWL, which occurs in the measles fusion protein (F438-446) and is an epitope for cytotoxic T lymphocytes. The peptides Pal-K(TMR)KKKRRYPDAVK(FL)L (7) and Pal-K(FL)KKKRRYPDAVK(TMR)L (8), in which Pal is palmitoyl and K-TMR and K-FL are N-epsilon-carboxytetramethylrhodamine- and N-epsilon-carboxyfluorescein-labeled lysyl residues, respectively, were prepared and obtained in approximate to 30% yield after purification by high-performance liquid chromatography. The fluorescence of fluorescein and tetramethylrhodamine in lipopeptide PalK(TMR)KKKRRYPDAVK(FL)L (7) was quenched to 98-99% due to intramolecular interaction of the labels. On incubation with trypsin (i.e. cleavage at the KKKRR-site) the fluorescence of both labels was restored. The intracellular routing of lipopeptide PalKTMRKKKRRYPDAVKFLL was studied with human melanoma cell line, Mel/J, which was transfected with human leukocyte antigen B*2705. It appeared that the double-fluorescent-labeled lipopeptide was able to induce antigen-specific cytotoxicity. Furthermore, preliminary confocal microscopical studies indicated that this lipopeptide is observed intracellularly.

28/10/2009