Discovery of potent inhibitors of dihydroneopterin aldolase using crystaLEAD high-throughput X-ray crystallographic screening and structure-directed lead optimization

Potent inhibitors of 7,8-dihydroneopterin aldolase (DHNA; EC 4.1.2.25) have been discovered using CrystaLEAD X-ray crystallographic high-throughput screening followed by structure-directed optimization. Screening of a 10 000 compound random library provided several low affinity leads and their corresponding X-ray crystal structures bound to the enzyme. The presence of a common structural feature in each of the leads suggested a strategy for the construction of a directed library of approximately 1000 compounds that were screened for inhibitory activity in a traditional enzyme assay. Several lead compounds with IC50 values of about 1 muM against DHNA were identified, and crystal structures of their enzyme-bound complex's were obtained by cocrystallization. Structure-directed optimization of one of the leads thus identified afforded potent inhibitors with submicromolar IC50 values.