Figure 4.

Schematic representation of the modular synthesis of chemical probes by DNA-technology. A binding strand, functionalized with a ligand that binds selectively to the protein of interest, is hybridized with a capture strand that contains a protein reactive group. In DPAL, the 3′ of the capture strand is functionalized with one of the depicted photocrosslinkers and the 5′-end of the capture strand contains a reporter group. In DTPC, the 3′ of the capture strand is functionalized with one of the depicted chemical crosslinkers and the 5′-end of the capture strand contains a reporter group. Upon binding of the ligand, the reactive group on the capture strand will covalently modify the protein of interest. The labeled proteins can be visualized via the reporter group on the capture strand.