Virtual screening and X-ray crystallography Identify non-substrate analog inhibitors of Flavin-dependent Thymidylate Synthase.

Thymidylate synthase X (ThyX) represents an attractive target for tuberculosis drug discovery. Herein, we selected 16 compounds through a virtual screening approach. We solved the first X-ray crystal structure Of Thermatoga maritima (Tm) ThyX in complex with a nonsubstrate analog inhibitor. Given the active site similarities between Mycobacterium tuberculosis ThyX (Mtb-ThyX) and Tm-ThyX, our crystal structure paves the way, for a structure-based design of novel antimycobacterial compounds. The 1H-imidazo[4,5-d]pyridazine was identified as scaffold for the development,of Mtb-ThyX inhibitors.