1fr6

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=AZR:2-({[(1Z)-1-(2-AMINO-1,3-THIAZOL-4-YL)-2-OXO-2-{[(2S,3S)-1-OXO-3-(SULFOAMINO)BUTAN-2-YL]AMINO}ETHYLIDENE]AMINO}OXY)-2-METHYLPROPANOIC+ACID'>AZR</scene></td></tr>

<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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== Publication Abstract from PubMed ==

Beta-Lactamases (EC 3.5.2.6, 'penicillinases') are a family of enzymes that protect bacteria against the lethal effects of cell-wall synthesis of penicillins, cephalosporins and related antibiotic agents, by hydrolysing the beta-lactam antibiotics to biologically inactive compounds. Their production can, therefore, greatly contribute to the clinical problem of antibiotic resistance. Three classes of beta-lactamases--A, B and C--have been identified on the basis of their amino-acid sequence; class B beta-lactamases are metalloenzymes, and are clearly distinct from members of class A and C beta-lactamases, which both contain an active-site serine residue involved in the formation of an acyl enzyme with beta-lactam substrates during catalysis. It has been predicted that class C beta-lactamases share common structural features with D,D-carboxypeptidases and class A beta-lactamases, and further, suggested that class A and class C beta-lactamases have the same evolutionary origin as other beta-lactam target enzymes. We report here the refined three-dimensional structure of the class C beta-lactamase from Citrobacter freundii at 2.0-A resolution and confirm the predicted structural similarity. The refined structure of the acyl-enzyme formed with the monobactam inhibitor aztreonam at 2.5-A resolution defines the enzyme's active site and, along with molecular modelling, indicates a mechanism for beta-lactam hydrolysis. This leads to the hypothesis that Tyr 150 functions as a general base during catalysis.

Refined crystal structure of beta-lactamase from Citrobacter freundii indicates a mechanism for beta-lactam hydrolysis.,Oefner C, D'Arcy A, Daly JJ, Gubernator K, Charnas RL, Heinze I, Hubschwerlen C, Winkler FK Nature. 1990 Jan 18;343(6255):284-8. PMID:2300174<ref>PMID:2300174</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 1fr6" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Beta-lactamase]]

[[Category: Arcy, A D]]

[[Category: Daly, J J]]

[[Category: Oefner, C]]

[[Category: Winkler, F K]]

[[Category: Monobactum]]