PNNL

Abstract

We have synthesized a targeted and releasable affinity probe (TRAP), consisting of a biarsenical fluorescein linked to benzophenone, and demonstrated the utility of TRAP to stabilize protein binding partners in living bacterial and mammalian systems upon photo-activation of the benzophenone moiety. Moreover, after covalent crosslinking, ligand exchange of the arsenic-sulfur bonds between TRAP and an engineered tetracysteine binding sequence within the target protein permits fluorophore transfer to the crosslinked binding partner, permitting the identification of the proximal binding interface of the isolated protein complex through mass spectrometric fragmentation and sequence identification.