NEW SYNTHETIC AMINO-ACIDS FOR THE DESIGN AND SYNTHESIS OF PEPTIDE-BASED METAL-ION SENSORS

The syntheses of two new nonstandard amino acids, Flu (6) and YBp (20) , and a new synthesis of Dmd (12) are reported. These residues exhibit fluorescence, metal-coordination, and fluorescence-quenching properti es, respectively. These building blocks have been incorporated into pe ptides via solid phase peptide synthesis to afford the prototype fur a photoinduced electron transfer-based metal ion chemosensor. The fluor escence of the peptides is modulated upon metal binding. This results from a metal. ion-induced conformational change that brings the side c hains of the Flu and Dmd amino acids into proximity, thereby favoring photoinduced electron transfer (PET) fluorescence quenching.