A chemoselective method for site-specific immobilization of peptides via aminooxy group

Site-specific modification of peptides and proteins is an important area of basic research for preparation of well-defined biosensors and probes. The unique properties of aminooxy group present an opportunity for chemoselecti ve site-specific immobilization of peptides to prepare well-defined biosens ors. We have prepared FLAG peptide derivatives containing L-is an element o f -aminooxylysine (L-zeta -AOLys, la) and L-lysine units in their sequence at the C- and N-terminals via solid-phase synthesis. Site-specific modifica tion of peptides through aminooxy group was demonstrated in the preparation of biosensors and selective conjugation in the preparation of biotinylated probes. Effect of the incorporation of L-is an element of -AOLys (1a) into the peptide sequence and its subsequent labeling on the FLAG epitopic char acter was measured using a surface plasmon resonance detector. It was found that incorporation of L-epsilon -AOLys (1a) into tile FLAG peptide and sit e-specific immobilization through aminooxy group preserved the integrity of FLAG epitope.