Identification of B. anthracis N5-carboxyaminoimidazole ribonucleotide mutase (PurE) active site binding compounds via fragment library screening. Issue 4 (15th February 2016)

• Record Type: Journal Article
• Authors: Lei, Hao; Jones, Christopher; Zhu, Tian; Patel, Kavankumar; Wolf, Nina M.; Fung, Leslie W.-M.; Lee, Hyun; Johnson, Michael E.
• Is Part Of: Bioorganic & medicinal chemistry. Volume 24:Issue 4(2016)
• Page Start: 596
• Page End: 605
• Publication Date: 2016-02-15
• Subjects: PurE N5-carboxyaminoimidazole ribonucleotide mutase -- FBDD fragment-based drug design -- NMR nuclear magnetic resonance -- STD-NMR saturation transfer difference nuclear magnetic resonance (NMR) -- WaterLOGSY NMR water ligand observed via gradient spectroscopy NMR -- SPR surface plasmon resonance -- TSA thermal shift assay -- N5-CAIR N5-carboxyaminoimidazole ribonucleotide -- CAIR 4-carboxyaminoimidazole ribonucleotide -- AIR aminoimidazole ribonucleotide; Bacillus anthracis -- PurE -- Fragment library screening -- SPR -- NMR; Bioorganic chemistry -- Periodicals; Pharmaceutical chemistry -- Periodicals; Biochemistry -- Periodicals; Chemistry, Clinical -- Periodicals; Chemistry, Organic -- Periodicals; Chimie bio-organique -- Périodiques; Chimie pharmaceutique -- Périodiques; 615.19
• DOI: 10.1016/j.bmc.2015.12.029
• Languages: English
• ISSNs: 0968-0896

Abstract

Graphical abstract: Abstract: The de novo purine biosynthesis pathway is an attractive target for antibacterial drug design, and PurE from this pathway has been identified to be crucial for Bacillus anthracis survival in serum. In this study we adopted a fragment-based hit discovery approach, using three screening methods—saturation transfer difference nucleus magnetic resonance (STD-NMR), water-ligand observed via gradient spectroscopy (WaterLOGSY) NMR, and surface plasmon resonance (SPR), against B. anthracis PurE ( Ba PurE) to identify active site binding fragments by initially testing 352 compounds in a Zenobia fragment library. Competition STD NMR with the Ba PurE product effectively eliminated non-active site binding hits from the primary hits, selecting active site binders only. Binding affinities (dissociation constant, K D ) of these compounds varied between 234 and 301 μM. Based on test results from the Zenobia compounds, we subsequently developed and applied a streamlined fragment screening strategy to screen a much larger library consisting of 3000 computationally pre-selected fragments. Thirteen final fragment hits were confirmed to exhibit binding affinities varying from 14 μM to 700 μM, which were categorized into five different basic scaffolds. All thirteen fragment hits have ligand efficiencies higher than 0.30. We demonstrated that at least two fragments from two different scaffolds exhibit inhibitory activity against the Ba PurE enzyme.