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| | <StructureSection load='7qq5' size='340' side='right'caption='[[7qq5]], [[Resolution|resolution]] 0.95Å' scene=''> | | <StructureSection load='7qq5' size='340' side='right'caption='[[7qq5]], [[Resolution|resolution]] 0.95Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[7qq5]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7QQ5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7QQ5 FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[7qq5]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Klebsiella_pneumoniae_IS53 Klebsiella pneumoniae IS53]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7QQ5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7QQ5 FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr> | + | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=DSN:D-SERINE'>DSN</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr> |
| - | <tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=DSN:D-SERINE'>DSN</scene></td></tr>
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| - | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Beta-lactamase Beta-lactamase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.2.6 3.5.2.6] </span></td></tr>
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| | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=7qq5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7qq5 OCA], [https://pdbe.org/7qq5 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7qq5 RCSB], [https://www.ebi.ac.uk/pdbsum/7qq5 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7qq5 ProSAT]</span></td></tr> | | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=7qq5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7qq5 OCA], [https://pdbe.org/7qq5 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7qq5 RCSB], [https://www.ebi.ac.uk/pdbsum/7qq5 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7qq5 ProSAT]</span></td></tr> |
| | </table> | | </table> |
| - | <div style="background-color:#fffaf0;">
| + | == Function == |
| - | == Publication Abstract from PubMed == | + | [[https://www.uniprot.org/uniprot/W1EPV7_KLEPN W1EPV7_KLEPN]] |
| - | beta-Lactamases hydrolyze beta-lactam antibiotics and are major determinants of antibiotic resistance in Gram-negative pathogens. Enmetazobactam (formerly AAI101) and tazobactam are penicillanic acid sulfone (PAS) beta-lactamase inhibitors that differ by an additional methyl group on the triazole ring of enmetazobactam, rendering it zwitterionic. In this study, ultrahigh-resolution X-ray crystal structures and mass spectrometry revealed the mechanism of PAS inhibition of CTX-M-15, an extended-spectrum beta-lactamase (ESBL) globally disseminated among Enterobacterales. CTX-M-15 crystals grown in the presence of enmetazobactam or tazobactam revealed loss of the Ser70 hydroxyl group and formation of a lysinoalanine cross-link between Lys73 and Ser70, two residues critical for catalysis. Moreover, the residue at position 70 undergoes epimerization, resulting in formation of a d-amino acid. Cocrystallization of enmetazobactam or tazobactam with CTX-M-15 with a Glu166Gln mutant revealed the same cross-link, indicating that this modification is not dependent on Glu166-catalyzed deacylation of the PAS-acylenzyme. A cocrystal structure of enmetazobactam with CTX-M-15 with a Lys73Ala mutation indicates that epimerization can occur without cross-link formation and positions the Ser70 Cbeta closer to Lys73, likely facilitating formation of the Ser70-Lys73 cross-link. A crystal structure of a tazobactam-derived imine intermediate covalently linked to Ser70, obtained after 30 min of exposure of CTX-M-15 crystals to tazobactam, supports formation of an initial acylenzyme by PAS inhibitors on reaction with CTX-M-15. These data rationalize earlier results showing CTX-M-15 deactivation by PAS inhibitors to involve loss of protein mass, and they identify a distinct mechanism of beta-lactamase inhibition by these agents. IMPORTANCE beta-Lactams are the most prescribed antibiotic class for treating bacterial diseases, but their continued efficacy is threatened by bacterial strains producing beta-lactamase enzymes that catalyze their inactivation. The CTX-M family of ESBLs are major contributors to beta-lactam resistance in Enterobacterales, preventing effective treatment with most penicillins and cephalosporins. Combining beta-lactams with beta-lactamase inhibitors (BLIs) is a validated route to overcome such resistance. Here, we describe how exposure to enmetazobactam and tazobactam, BLIs based on a penicillanic acid sulfone (PAS) scaffold, leads to a protein modification in CTX-M-15, resulting in irremediable inactivation of this most commonly encountered member of the CTX-M family. High-resolution X-ray crystal structures showed that PAS exposure induces formation of a cross-link between Ser70 and Lys73, two residues critical to beta-lactamase function. This previously undescribed mechanism of inhibition furthers our understanding of beta-lactamase inhibition by classical PAS inhibitors and provides a basis for further, rational inhibitor development.
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| - | Penicillanic Acid Sulfones Inactivate the Extended-Spectrum beta-Lactamase CTX-M-15 through Formation of a Serine-Lysine Cross-Link: an Alternative Mechanism of beta-Lactamase Inhibition.,Hinchliffe P, Tooke CL, Bethel CR, Wang B, Arthur C, Heesom KJ, Shapiro S, Schlatzer DM, Papp-Wallace KM, Bonomo RA, Spencer J mBio. 2022 Jun 28;13(3):e0179321. doi: 10.1128/mbio.01793-21. Epub 2022 May 25. PMID:35612361<ref>PMID:35612361</ref>
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| - | | + | |
| - | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
| + | |
| - | </div>
| + | |
| - | <div class="pdbe-citations 7qq5" style="background-color:#fffaf0;"></div>
| + | |
| - | == References ==
| + | |
| - | <references/>
| + | |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Beta-lactamase]] | + | [[Category: Klebsiella pneumoniae IS53]] |
| | [[Category: Large Structures]] | | [[Category: Large Structures]] |
| - | [[Category: Hinchliffe, P]] | + | [[Category: Hinchliffe P]] |
| - | [[Category: Spencer, J]] | + | [[Category: Spencer J]] |
| - | [[Category: Tooke, C L]] | + | [[Category: Tooke CL]] |
| - | [[Category: Antibiotic resistance]]
| + | |
| - | [[Category: Antimicrobial protein]]
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| - | [[Category: Cross-link]]
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| - | [[Category: Inhibitor]]
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