References of "Offant, Julien"
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See detailSmall molecule inhibitors of peptidoglycan synthesis targeting the lipid II precursor.
Derouaux, Adeline ULg; Turk, Samo; Olrichs, Nick K et al

in Biochemical Pharmacology (2011), 81(9), 1098-105

Bacterial peptidoglycan glycosyltransferases (GTs) of family 51 catalyze the polymerization of the lipid II precursor into linear peptidoglycan strands. This activity is essential to bacteria and ... [more ▼]

Bacterial peptidoglycan glycosyltransferases (GTs) of family 51 catalyze the polymerization of the lipid II precursor into linear peptidoglycan strands. This activity is essential to bacteria and represents a validated target for the development of new antibacterials. Application of structure-based virtual screening to the National Cancer Institute library using eHits program and the structure of the glycosyltransferase domain of the Staphylococcus aureus penicillin-binding protein 2 resulted in the identification of two small molecules analogues 5, a 2-[1-[(2-chlorophenyl)methyl]-2-methyl-5-methylsulfanylindol-3-yl]ethanamine and 5b, a 2-[1-[(3,4-dichlorophenyl)methyl]-2-methyl-5-methylsulfanylindol-3-yl]ethanamine that exhibit antibacterial activity against several Gram-positive bacteria but were less active on Gram-negative bacteria. The two compounds inhibit the activity of five GTs in the micromolar range. Investigation of the mechanism of action shows that the compounds specifically target peptidoglycan synthesis. Unexpectedly, despite the fact that the compounds were predicted to bind to the GT active site, compound 5b was found to interact with the lipid II substrate via the pyrophosphate motif. In addition, this compound showed a negatively charged phospholipid-dependent membrane depolarization and disruption activity. These small molecules are promising leads for the development of more active and specific compounds to target the essential GT step in cell wall synthesis. [less ▲]

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See detailOptimization of conditions for the glycosyltransferase activity of penicillin-binding protein 1a from Thermotoga maritima.
Offant, Julien; Terrak, Mohammed ULg; Derouaux, Adeline ULg et al

in FEBS Journal (2010), 277(20), 4290-8

Cell wall biosynthesis is a key target for antibacterial drugs. The major constituent of the bacterial wall, peptidoglycan, is a netlike polymer responsible for the size and shape of the cell and for ... [more ▼]

Cell wall biosynthesis is a key target for antibacterial drugs. The major constituent of the bacterial wall, peptidoglycan, is a netlike polymer responsible for the size and shape of the cell and for resisting osmotic pressure. It consists of glycan chains of repeating disaccharide units cross-linked through short peptide chains. Peptidoglycan assembly is catalyzed by the periplasmic domain of bifunctional class A penicillin-binding proteins. Cross-linking of the peptide chains is catalyzed by their transpeptidase module, which can be inhibited by the most widely used antibiotics, the beta-lactams. In contrast, no drug in clinical use inhibits the polymerization of the glycan chains, catalyzed by their glycosyltransferase module, although it is an obvious target. We report here the purification of the ectodomain of the class A penicillin-binding protein 1a from Thermotoga maritima (Tm-1a*), expressed recombinantly in Escherichia coli. A detergent screen showed that detergents with shorter aliphatic chains were better solubilizers. Cyclohexyl-hexyl-beta-D-maltoside-purified Tm-1a* was found to be monomeric and to have improved thermal stability. A miniaturized, multiwell continuous fluorescence assay of the glycosyltransferase activity was used to screen for optimal reaction conditions. Tm-1a* was active as a glycosyltransferase, catalyzing the formation of glycan chains up to 16 disaccharide units long. Our results emphasize the importance of the detergent in preparing a stable monomeric ectodomain of a class A penicillin-binding protein. Our assay could be used to screen collections of compounds for inhibitors of peptidoglycan glycosyltransferases that could serve as the basis for the development of novel antibiotics. [less ▲]

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See detailIdentification and characterization of novel peptidoglycan glycosyltransferase inhibitors with antibacterial activity
Derouaux, Adeline ULg; Turk, Samo; Offant, Julien et al

Poster (2009, November)

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