View source for 4ibx


==Crystal structure of stabilized TEM-1 beta-lactamase variant v.13==
<StructureSection load='4ibx' size='340' side='right'caption='[[4ibx]], [[Resolution|resolution]] 2.68&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4ibx]] is a 5 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=4IBX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4IBX 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]] 2.68&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=MES:2-(N-MORPHOLINO)-ETHANESULFONIC+ACID'>MES</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=4ibx FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4ibx OCA], [https://pdbe.org/4ibx PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4ibx RCSB], [https://www.ebi.ac.uk/pdbsum/4ibx PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4ibx ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/BLAT_ECOLX BLAT_ECOLX] TEM-type are the most prevalent beta-lactamases in enterobacteria; they hydrolyze the beta-lactam bond in susceptible beta-lactam antibiotics, thus conferring resistance to penicillins and cephalosporins. TEM-3 and TEM-4 are capable of hydrolyzing cefotaxime and ceftazidime. TEM-5 is capable of hydrolyzing ceftazidime. TEM-6 is capable of hydrolyzing ceftazidime and aztreonam. TEM-8/CAZ-2, TEM-16/CAZ-7 and TEM-24/CAZ-6 are markedly active against ceftazidime. IRT-4 shows resistance to beta-lactamase inhibitors.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Protein evolvability includes two elements-robustness (or neutrality, mutations having no effect) and innovability (mutations readily inducing new functions). How are these two conflicting demands bridged? Does the ability to bridge them relate to the observation that certain folds, such as TIM barrels, accommodate numerous functions, whereas other folds support only one? Here, we hypothesize that the key to innovability is polarity-an active site composed of flexible, loosely packed loops alongside a well-separated, highly ordered scaffold. We show that highly stabilized variants of TEM-1 beta-lactamase exhibit selective rigidification of the enzyme's scaffold while the active-site loops maintained their conformational plasticity. Polarity therefore results in stabilizing, compensatory mutations not trading off, but instead promoting the acquisition of new activities. Indeed, computational analysis indicates that in folds that accommodate only one function throughout evolution, for example, dihydrofolate reductase, &gt;/=60% of the active-site residues belong to the scaffold. In contrast, folds associated with multiple functions such as the TIM barrel show high scaffold-active-site polarity (~20% of the active site comprises scaffold residues) and &gt;2-fold higher rates of sequence divergence at active-site positions. Our work suggests structural measures of fold polarity that appear to be correlated with innovability, thereby providing new insights regarding protein evolution, design, and engineering.

What Makes a Protein Fold Amenable to Functional Innovation? Fold Polarity and Stability Trade-offs.,Dellus-Gur E, Toth-Petroczy A, Elias M, Tawfik DS J Mol Biol. 2013 Mar 28. pii: S0022-2836(13)00200-3. doi:, 10.1016/j.jmb.2013.03.033. PMID:23542341<ref>PMID:23542341</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4ibx" 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: Dellus-Gur E]]
[[Category: Elias M]]
[[Category: Tawfik DS]]
[[Category: Toth-Petroczy A]]