Fig. 6.

The binding of 6 into the PqsR LBD as a surface representation (a), and the key binding interactions observed between the carbonyl of 6 and Thr265, and the sulfur atom of 6 and Tyr258 (b). Below these are analogous representations for 12 (c–d), 18 (e–f) and 19 (g–h). In each surface representation the chlorine atom is buried deep into the B pocket, anchoring the ligand in place. Binding modes are seen to be similar in each example, with the hydroxyl of Thr265 turned to face the carbonyl of the quinazolinone, thereby eliciting a H-bond. Furthermore, the sulfur is angled towards the phenol of Tyr258 enabling a polar interaction.