Conformational flexibility of the glycosidase NagZ allows it to bind structurally diverse inhibitors to suppress β‐lactam antibiotic resistance

• DOI: 10.1002/pro.3166
• Publication Date: 2017-03-28T08:53:47Z
• Authors: Grishma Vadlamani; Keith A. Stubbs; Jérôme Désiré; Yves Blériot; David J. Vocadlo; Brian L. Mark
• Keywords: Moiety; Hydrolase; Residue (chemistry)

NagZ is an N-acetyl-β-d-glucosaminidase that participates in the peptidoglycan (PG) recycling pathway of Gram-negative bacteria by removing N-acetyl-glucosamine (GlcNAc) from PG fragments have been excised cell wall during growth. The 1,6-anhydromuramoyl-peptide products generated activate β-lactam resistance many inducing expression AmpC β-lactamase. Blocking activity can thereby suppress antibiotic these bacteria. active site dynamic and it accommodates distortion glycan substrate catalysis using a mobile catalytic loop carries histidine residue which serves as general acid/base catalyst. Here, we show flexibility this also structural differences small molecule inhibitors NagZ, could be exploited to improve inhibitor specificity. X-ray structures bound potent yet non-selective N-acetyl-β-glucosaminidase PUGNAc (O-(2-acetamido-2-deoxy-d-glucopyranosylidene) amino-N-phenylcarbamate), two NagZ-selective - EtBuPUG, derivative bearing 2-N-ethylbutyryl group, MM-156, 3-N-butyryl trihydroxyazepane, revealed phenylcarbamate moiety EtBuPUG completely displaces yield catalytically incompetent form enzyme. In contrast, was found positioned conformation within when lacks extension. Displacement its N-acyl alters presents additional strategy potency specificity inhibitors.