6H2I
Structure of BlaC from Mycobacterium tuberculosis bound to the trans-enamine adduct of tazobactam.
Summary for 6H2I
| Entry DOI | 10.2210/pdb6h2i/pdb |
| Descriptor | Beta-lactamase, TAZOBACTAM INTERMEDIATE, ACETATE ION, ... (4 entities in total) |
| Functional Keywords | hydrolase |
| Biological source | Mycobacterium tuberculosis |
| Total number of polymer chains | 2 |
| Total formula weight | 59672.82 |
| Authors | Tassoni, R.,Pannu, N.S.,Ubbink, M. (deposition date: 2018-07-13, release date: 2019-01-23, Last modification date: 2024-11-13) |
| Primary citation | Tassoni, R.,Blok, A.,Pannu, N.S.,Ubbink, M. New Conformations of Acylation Adducts of Inhibitors of beta-Lactamase from Mycobacterium tuberculosis. Biochemistry, 58:997-1009, 2019 Cited by PubMed Abstract: Mycobacterium tuberculosis (Mtb), the main causative agent of tuberculosis (TB), is naturally resistant to β-lactam antibiotics due to the production of the extended spectrum β-lactamase BlaC. β-Lactam/β-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 β-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 Sγ atom to the nearby amino group of lysine 73. The differences of adduct conformations between BlaC and other β-lactamases are discussed. PubMed: 30632739DOI: 10.1021/acs.biochem.8b01085 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.72 Å) |
Structure validation
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