Fluorescent amino acid initiated de novo cyclic peptides for the label-free assessment of cell permeability

More about Open Access at the Crick


The major obstacle in applying peptides to intracellular targets is their low inherent cell permeability. Standard approaches to attach a fluorophore (e.g. FITC, TAMRA) can change the physicochemical properties of the parent peptide and influence their ability to penetrate and localize in cells. We report a label-free strategy for evaluating the cell permeability of cyclic peptide leads. Fluorescent tryptophan analogues 4-cyanotryptophan (4CNW) and beta-(1-azulenyl)-L-alanine (AzAla) were incorporated into in vitro translated macrocyclic peptides by initiator reprogramming. We then demonstrate these efficient blue fluorescent emitters are good tools for monitoring peptide penetration into cells.

Journal details

Journal ChemMedChem
Volume 16
Issue number 20
Pages 3185-3188
Available online
Publication date