6h2c

Structure of BlaC from Mycobacterium tuberculosis bound to the trans-enamine adduct derived from clavulanic acid.

spinqualitylabelsall models 6h2c, resolution 1.93Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6h2c is a 2 chain structure with sequence from Mycobacterium tuberculosis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.93Å Ligands: 15P, ACT, CO2, GOL, ISS Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Mycobacterium tuberculosis (Mtb), the main causative agent of tuberculosis (TB), is naturally resistant to beta-lactam antibiotics due to the production of the extended spectrum beta-lactamase BlaC. beta-Lactam/beta-lactamase inhibitor combination therapies can circumvent the BlaC-mediated resistance of Mtb and are promising treatment options against TB. However, still little is known of the exact mechanism of BlaC inhibition by the beta-lactamase inhibitors currently approved for clinical use, clavulanic acid, sulbactam, tazobactam, and avibactam. Here, we present the X-ray diffraction crystal structures of the acyl-enzyme adducts of wild-type BlaC with the four inhibitors. The +70 Da adduct derived from clavulanate and the trans-enamine acylation adducts of sulbactam and tazobactam are reported. BlaC in complex with avibactam revealed two inhibitor conformations. Preacylation binding could not be observed because inhibitor binding was not detected in BlaC variants carrying a substitution of the active site serine 70 to either alanine or cysteine, by crystallography, ITC or NMR. These results suggest that the catalytic serine 70 is necessary not only for enzyme acylation but also for increasing BlaC affinity for inhibitors in the preacylation state. The structure of BlaC with the serine to cysteine mutation showed a covalent linkage of the cysteine 70 Sgamma atom to the nearby amino group of lysine 73. The differences of adduct conformations between BlaC and other beta-lactamases are discussed. New Conformations of Acylation Adducts of Inhibitors of beta-Lactamase from Mycobacterium tuberculosis.,Tassoni R, Blok A, Pannu NS, Ubbink M Biochemistry. 2019 Feb 19;58(7):997-1009. doi: 10.1021/acs.biochem.8b01085. Epub , 2019 Jan 30. PMID:30632739 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Beta-lactamase 3D structures

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