Fluorescent labeling of peptides on solid phase

Abstract

N(alpha)-Fmoc-N(epsilon)-[(7-methoxycoumarin-4-yl)acetyl]-L-lysine (N(alpha)-Fmoc-L-Lys(Mca)-OH) 3 is conveniently prepared by benzotriazole methodology (52% over two steps). N-Acylbenzotriazoles Mca-Bt 2, N(alpha)-Fmoc-L-Lys(Mca)-Bt 4, coumarin-3-ylcarbonyl (Cc)-Bt 5, N(alpha)-Fmoc-L-Lys(Cc)-Bt 7 and N(alpha)-(Cc)-L-Lys(Fmoc)-Bt 9 enable the efficient microwave enhanced solid-phase fluorescent labeling of peptides.

Chiral Acylation with N-(Protected α-Aminoacyl)benzotriazoles for Advantageous Syntheses of Peptides and Peptide Conjugates

“…69 We also prepared fluorescent peptides on solid phase by acylation with benzotriazole-activated derivatives of (i) coumarin-3-carboxylic acid and 7-methoxycoumarin-4acetic acid, and (ii) coumarin-3-ylcarbonyl (Cc)-and 7methoxycoumarin-4-ylacetyl (Mca)-labeled lysines. 70 The fluorescent peptides were obtained under microwave irradiation in 18-45% purified yield (Scheme 13 and Table 13). Absorption and fluorescence wavelength maxima were measured for all synthesized fluorescent peptides.…”

Combinatorial Strategies in Fluorescent Probe Development

“…A few methods to incorporate fluorescent tags in peptide libraries have been described. Rademann and co-workers optimized the preparation of fluorescein-labeled peptides, whereas Ellman’s and Katritzky’s laboratories worked on coumarin derivatives. , Unnatural amino acids containing fluorogenic motifs or FRET pairs , are useful tools but are rather used to study protein–protein interactions than to develop fluorescent probes. Split-and-mix libraries of fluorescent peptides have been also reported as optical encoding tools …”

Solid‐Phase Synthesis of Dyes and their Application as Sensors and Bioimaging Probes

“…Fluorescent peptides can be prepared by incorporating unnatural amino acids including a reporter (e.g., fluorogenic, solvatochromic) that is compatible with solidphase peptide synthesis protocols. [16][17][18] These approaches impart a minor change in the peptide structure, but require some prior knowledge of the residue within the sequence that can be modified without altering the properties of the peptide. More versatile strategies have been devised by loading a fluorophore (e.g., coumarin, fluorescein) as the C-terminal amino acid and building the rest of the peptide afterward.…”