Identification of small molecules that disrupt SSB-protein interactions using a high-throughput screen.

Bacterial single-stranded DNA-binding proteins (SSBs) recruit a diverse array of genome maintenance enzymes to their sites of action through direct protein interactions. The essential nature of these SSB-protein interactions makes inhibitors that block SSB-partner complex formation valuable biochemical tools and attractive potential antibacterial agents. However, many of these protein-protein interactions are weak and not amenable to the high-throughput nature of small molecule screens. Here I describe a high-throughput screen to identify small molecules that inhibit the interaction between Exonuclease I (ExoI) and the final 10 amino acids of the SSB C-terminal tail (SSB-Ct). The strength of the binding between ExoI and the SSB-Ct tail is fundamental to the interaction's utility in the high-throughput screen.