Synthesis and characterization of bifunctional probes for the specific labeling of fusion proteins

Labeling proteins with synthetic probes is important for studying and characterizing protein function. We have recently introduced a general method for the specific in vivo and in vitro labeling of fusion proteins that is based on the reaction of O-6-alkylguanine-DNA alkyltransferase (AGT) with O-6-benzylguanine derivatives. Here we report two complementary routes for the synthesis of O-6-benzylguanine derivatives, which allow for the labeling of AGT fusion proteins with bifunctional synthetic probes and demonstrate the specific labeling of AGT fusion proteins with these probes. These molecules should become useful tools for various applications in functional proteomics. (C) 2004 Elsevier Ltd. All rights reserved.