Identification and optimization of Escherichia coli GlmU inhibitors: an in silico approach with validation thereof

Bacterial infections are causing havoc on the populace. Continuous rising of antibiotic resistance in bacteria causes pressing requirement of new drugs and drug therapies that are effective against these multidrug resistance bacteria. GlmU, which is a bifunctional acetyltransferase/uridyltransferase enzyme, is novel target to treat bacterial infections. An effort has been made to identify and develop novel inhibitors of acetyltransferase activity of Escherichia coli (Ec) GlmU protein. In silico approach has been applied to screen chemical library of 50,000 drug-like compounds procured from ChemBridge and ChemDiv databases. This chemical library was screened by using a combination of ligand guided and structure guided techniques. In vitro evaluation of the in silico identified hits helped in the discovery of 8 promising inhibitors of acetyltransferase activity of Ec GlmU. Structure guided lead optimization strategy was adopted based on the acetyltransferase binding site analysis, that presented the scope of modification around three different structural moieties identified through in vitro hits. In addition, molecular dynamics studies revealed the stability of the protein-inhibitor complexes of the two most promising inhibitors identified in this study.