Figure 2.

Structures of published PBD/Plk1 inhibitors. Only the inhibitors discussed in the text are shown. Arrows indicate sites of nucleophilic attacks by amino-acid side chains leading to a covalent bond (alkylation of the protein). Shown is the potency (IC₅₀) of each molecule for the inhibition of PBD domains measured in fluorescence polarization assays or GST pulldown (Purpurogallin). See indicated references for details. Rigosertib is reported as a non-ATP-competitive inhibitor of Plk1 kinase and has not been shown to interfere with the PBD. The asterisk indicates a suspected site of nucleophilic attack.