View source for 4mbk


==Crystal structure of K234R inhibitor-resistant variant of SHV beta-lactamase in complex with SA2-13==
<StructureSection load='4mbk' size='340' side='right'caption='[[4mbk]], [[Resolution|resolution]] 1.46&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4mbk]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Klebsiella_pneumoniae Klebsiella pneumoniae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4MBK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4MBK 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]] 1.46&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MA4:CYCLOHEXYL-HEXYL-BETA-D-MALTOSIDE'>MA4</scene>, <scene name='pdbligand=SA2:(3R)-4-[(4-CARBOXYBUTANOYL)OXY]-N-[(1E)-3-OXOPROP-1-EN-1-YL]-3-SULFINO-D-VALINE'>SA2</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=4mbk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4mbk OCA], [https://pdbe.org/4mbk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4mbk RCSB], [https://www.ebi.ac.uk/pdbsum/4mbk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4mbk ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/BLA1_KLEPN BLA1_KLEPN] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
beta-Lactamases are the major reason beta-lactam resistance is seen in Gram-negative bacteria. To combat this resistance mechanism, beta-lactamase inhibitors are currently being developed. Presently, there are only three that are in clinical use (clavulanate, sulbactam and tazobactam). In order to address this important medical need, we explored a new inhibition strategy that takes advantage of a long-lived inhibitory trans-enamine intermediate. SA2-13 was previously synthesized and shown to have a lower k(react) than tazobactam. We investigated here the importance of the carboxyl linker length and composition by synthesizing three analogs of SA2-13 (PSR-4-157, PSR-4-155, and PSR-3-226). All SA2-13 analogs yielded higher turnover numbers and k(react) compared to SA2-13. We next demonstrated using protein crystallography that increasing the linker length by one carbon allowed for better capture of a trans-enamine intermediate; in contrast, this trans-enamine intermediate did not occur when the C2 linker length was decreased by one carbon. If the linker was altered by both shortening it and changing the carboxyl moiety into a neutral amide moiety, the stable trans-enamine intermediate in wt SHV-1 did not form; this intermediate could only be observed when a deacylation deficient E166A variant was studied. We subsequently studied SA2-13 against a relatively recently discovered inhibitor-resistant (IR) variant of SHV-1, SHV K234R. Despite the alteration in the mechanism of resistance due to the K--&gt;R change in this variant, SA2-13 was effective at inhibiting this IR enzyme and formed a trans-enamine inhibitory intermediate similar to the intermediate seen in the wt SHV-1 structure. Taken together, our data reveals that the C2 side chain linker length and composition profoundly affect the formation of the trans-enamine intermediate of penam sulfones. We also show that the design of SA2-13 derivatives offers promise against IR SHV beta-lactamases that possess the K234R substitution.

Penam sulfones and beta-lactamase inhibition: SA2-13 and the importance of the C2 side chain length and composition.,Rodkey EA, Winkler ML, Bethel CR, Pagadala SR, Buynak JD, Bonomo RA, van den Akker F PLoS One. 2014 Jan 16;9(1):e85892. doi: 10.1371/journal.pone.0085892. eCollection, 2014. PMID:24454944<ref>PMID:24454944</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4mbk" style="background-color:#fffaf0;"></div>

==See Also==
*[[Beta-lactamase 3D structures|Beta-lactamase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Klebsiella pneumoniae]]
[[Category: Large Structures]]
[[Category: Rodkey EA]]
[[Category: Van den Akker F]]