title: Tuning the moenomycin pharmacophore to enable discovery of bacterial cell wall synthesis inhibitors.
abstract: New antibiotic drugs need to be identified to address rapidly developing resistance of bacterial pathogens to common antibiotics. The natural antibiotic moenomycin A is the prototype for compounds that bind to bacterial peptidoglycan glycosyltransferases (PGTs) and inhibit cell wall biosynthesis, but it cannot be used as a drug. Here we report the chemoenzymatic synthesis of a fluorescently labeled, truncated analogue of moenomycin based on the minimal pharmacophore. This probe, which has optimized enzyme binding properties compared to moenomycin, was designed to identify low-micromolar inhibitors that bind to conserved features in PGT active sites. We demonstrate its use in displacement assays using PGTs from S. aureus, E. faecalis, and E. coli. 110,000 compounds were screened against S. aureus SgtB, and we identified a non-carbohydrate based compound that binds to all PGTs tested. We also show that the compound inhibits in vitro formation of peptidoglycan chains by several different PGTs. Thus, this assay enables the identification of small molecules that target PGT active sites, and may provide lead compounds for development of new antibiotics.
authors: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors: Christian M
authors: CM
authors: Gampe
authors: Hirokazu
authors: H
authors: Tsukamoto
authors: Emma H
authors: EH
authors: Doud
authors: Suzanne
authors: S
authors: Walker
authors: Daniel
authors: D
authors: Kahne
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis / Q000737:chemistry / Q000494:pharmacology*; D001455:Bambermycins / Q000096:biosynthesis / Q000737:chemistry / Q000494:pharmacology*; D002473:Cell Wall / Q000187:drug effects* / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D046928:Peptidoglycan Glycosyltransferase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013211:Staphylococcus aureus / Q000166:cytology / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D001455:Bambermycins; C437243:moenomycin A; D046928:Peptidoglycan Glycosyltransferase