SYNTHESIS OF PEPTIDES WITH FLUORESCENT TAGS

Abstract

Covalently linked acceptor-spacer-donor (A-S-D) multichromophoric systems have previously been discussed largely in mechanistic terms, with emphasis on the roles of electronic and nuclear functions in determining the factors of internal electron transfer. Electron energy transfer between donor (D) and acceptor (A) molecules has long been applied to measure or estimate distance in macromolecular systems, molecular stacking, intramolecular changes caused by ionic strength or target molecule binding, to define protein folding and aggregation and finally to give information about conformational changes in the molecule. Coumarins represent a family of dyes that often play the role of electron donor in electron-charged systems. During tailoring of new chromophore dyads, coumarin derivatives have been linked to fullerene, peptides, and dyes (benzimidazol benzopyrans). In particular, 7-methoxy-2-oxo-2H-chromene-3-carboxylic acid is a commonly used tag that provides strong fluorescence and acts as an electron-donor. In current work we are developing chiral systems of 10 Å and more in order to establish a structure map whenever the donor-acceptor fluorophore is conjugating with another system (e. g. peptides). Our team enhances the fluorescence of the two coumarin-based fluorophores by linking them to the N- and C-peptide moieties via 1,2,3-triazine linkers.