View source for 1iyq


==Toho-1 beta-Lactamase In Complex With Benzylpenicillin==
<StructureSection load='1iyq' size='340' side='right'caption='[[1iyq]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1iyq]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1IYQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1IYQ 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]] 2.1&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=PNM:OPEN+FORM+-+PENICILLIN+G'>PNM</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=1iyq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1iyq OCA], [https://pdbe.org/1iyq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1iyq RCSB], [https://www.ebi.ac.uk/pdbsum/1iyq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1iyq ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/BLT1_ECOLX BLT1_ECOLX] Has strong cefotaxime-hydrolyzing activity.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/iy/1iyq_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1iyq ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Bacterial resistance to beta-lactam antibiotics is a serious problem limiting current clinical therapy. The most common form of resistance is the production of beta-lactamases that inactivate beta-lactam antibiotics. Toho-1 is an extended-spectrum beta-lactamase that has acquired efficient activity not only to penicillins but also to cephalosporins including the expanded-spectrum cephalosporins that were developed to be stable in former beta-lactamases. We present the acyl-intermediate structures of Toho-1 in complex with cefotaxime (expanded-spectrum cephalosporin), cephalothin (non-expanded-spectrum cephalosporin), and benzylpenicillin at 1.8-, 2.0-, and 2.1-A resolutions, respectively. These structures reveal distinct features that can explain the ability of Toho-1 to hydrolyze expanded-spectrum cephalosporins. First, the Omega-loop of Toho-1 is displaced to avoid the steric contacts with the bulky side chain of cefotaxime. Second, the conserved residues Asn(104) and Asp(240) form unique interactions with the bulky side chain of cefotaxime to fix it tightly. Finally, the unique interaction between the conserved Ser(237) and cephalosporins probably helps to bring the beta-lactam carbonyl group to the suitable position in the oxyanion hole, thus increasing the cephalosporinase activity.

Acyl-intermediate structures of the extended-spectrum class A beta-lactamase, Toho-1, in complex with cefotaxime, cephalothin, and benzylpenicillin.,Shimamura T, Ibuka A, Fushinobu S, Wakagi T, Ishiguro M, Ishii Y, Matsuzawa H J Biol Chem. 2002 Nov 29;277(48):46601-8. Epub 2002 Sep 8. PMID:12221102<ref>PMID:12221102</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 1iyq" style="background-color:#fffaf0;"></div>

==See Also==
*[[Beta-lactamase 3D structures|Beta-lactamase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Fushinobu S]]
[[Category: Ibuka A]]
[[Category: Ishiguro M]]
[[Category: Ishii Y]]
[[Category: Matsuzawa H]]
[[Category: Shimamura T]]
[[Category: Wakagi T]]