Fig. 1: Design of cryptic sites in a synthetic ECM using switch peptides.
From: Activating hidden signals by mimicking cryptic sites in a synthetic extracellular matrix
A Schematic illustration of synthetic ECM with switch peptides as cryptic site mimics. Cell surface enzymes remove an amino acid residue, activating the switch peptide and forming the cell-adhesive YIGSR sequence. B Chemical transformation of the switch peptide KSYIGR containing a “split sequence” where the Ser residue is attached to a side chain YIG sequence (red) through its side chain alcohol, forming an ester bond. Removal of the N-terminal Lys residue by added trypsin reveals the free Ser amine (intermediate peptide). Once the free amine is present, a spontaneous O → N acyl shift occurs, generating the native peptide bond and forming the functional YIGSR peptide (blue). Other examples in this report use a membrane enzyme to trigger the switch. C MALDI-TOF MS spectra of switch peptide after incubation with trypsin for different time points. Peak m/z = 764 ([M + H]+) indicates the switch peptide, while m/z = 636 ([M + H]+) indicates the functional peptide.
