View source for 7khy


==Crystal structure of OXA-163 K73A in complex with meropenem==
<StructureSection load='7khy' size='340' side='right'caption='[[7khy]], [[Resolution|resolution]] 1.84&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7KHY OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7KHY FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.84&#8491;</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=MER:(4R,5S)-3-{[(3S,5S)-5-(DIMETHYLCARBAMOYL)PYRROLIDIN-3-YL]SULFANYL}-5-[(2S,3R)-3-HYDROXY-1-OXOBUTAN-2-YL]-4-METHYL-4,5-DIHYDRO-1H-PYRROLE-2-CARBOXYLIC+ACID'>MER</scene>, <scene name='pdbligand=MPD:(4S)-2-METHYL-2,4-PENTANEDIOL'>MPD</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></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=7khy FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7khy OCA], [https://pdbe.org/7khy PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7khy RCSB], [https://www.ebi.ac.uk/pdbsum/7khy PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7khy ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
Carbapenem-hydrolyzing class D beta-lactamases (CHDLs) are an important source of resistance to these last resort beta-lactam antibiotics. OXA-48 is a member of a group of CHDLs named OXA-48-like enzymes. On the basis of sequence similarity, OXA-163 can be classified as an OXA-48-like enzyme, but it has altered substrate specificity. Compared to OXA-48, it shows impaired activity for carbapenems but displays an enhanced hydrolysis of oxyimino-cephalosporins. Here, we address the mechanistic and structural basis for carbapenem hydrolysis by OXA-48-like enzymes. Pre-steady-state kinetic analysis indicates that the rate-limiting step for OXA-48 and OXA-163 hydrolysis of carbapenems is deacylation and that the greatly reduced carbapenemase activity of OXA-163 compared to that of OXA-48 is due entirely to a slower deacylation reaction. Furthermore, our structural data indicate that the positioning of the beta5-beta6 loop is necessary for carbapenem hydrolysis by OXA-48. A major difference between the OXA-48 and OXA-163 complexes with carbapenems is that the 214-RIEP-217 deletion in OXA-163 creates a large opening in the active site that is absent in the OXA-48/carbapenem structures. We propose that the larger active site results in less constraint on the conformation of the 6alpha-hydroxyethyl group in the acyl-enzyme. The acyl-enzyme intermediate assumes multiple conformations, most of which are incompatible with rapid deacylation. Consistent with this hypothesis, molecular dynamics simulations indicate that the most stable complex is formed between OXA-48 and imipenem, which correlates with the OXA-48 hydrolysis of imipenem being the fastest observed. Furthermore, the OXA-163 complexes with imipenem and meropenem are the least stable and show significant conformational fluctuations, which correlates with the slow hydrolysis of these substrates.

Mechanistic Basis of OXA-48-like beta-Lactamases' Hydrolysis of Carbapenems.,Stojanoski V, Hu L, Sankaran B, Wang F, Tao P, Prasad BVV, Palzkill T ACS Infect Dis. 2021 Jan 25. doi: 10.1021/acsinfecdis.0c00798. PMID:33492952<ref>PMID:33492952</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 7khy" style="background-color:#fffaf0;"></div>

==See Also==
*[[Beta-lactamase 3D structures|Beta-lactamase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Hu L]]
[[Category: Palzkill T]]
[[Category: Prasad BVV]]