View source for 4lnj


==Structure of Escherichia coli Threonine Aldolase in Unliganded Form==
<StructureSection load='4lnj' size='340' side='right'caption='[[4lnj]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4lnj]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_WV_060327 Escherichia coli WV_060327]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4LNJ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4LNJ 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=EPE:4-(2-HYDROXYETHYL)-1-PIPERAZINE+ETHANESULFONIC+ACID'>EPE</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=PLR:(5-HYDROXY-4,6-DIMETHYLPYRIDIN-3-YL)METHYL+DIHYDROGEN+PHOSPHATE'>PLR</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=4lnj FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4lnj OCA], [https://pdbe.org/4lnj PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4lnj RCSB], [https://www.ebi.ac.uk/pdbsum/4lnj PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4lnj ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
L-Threonine aldolases (TAs) represent a family of homologous pyridoxal 5'-phosphate-dependent enzymes found in bacteria and fungi, and catalyse the reversible cleavage of several L-3-hydroxy-alpha-amino acids. TAs have great biotechnological potential, since they catalyse the formation of carbon-carbon bonds, and therefore may be exploited for bioorganic synthesis of L-3-hydroxyamino acids that are biologically active or constitute building blocks for pharmaceutical molecules. Many TAs, showing different stereospecificity towards the Cbeta configuration, have been isolated. Because of their potential to carry out diastereoselective syntheses, TAs have been the subject of structural, functional and mechanistic studies. Nevertheless, their catalytic mechanism and the structural bases of their stereospecificity have not been elucidated. In this study, we have determined the crystal structure of low-specificity L-threonine aldolase from Escherichia coli at 2.2 A resolution, in the unliganded form and co-crystallized with L-serine and L-threonine. Furthermore, several active-site mutants have been functionally characterised in order to elucidate the reaction mechanism and the molecular bases of stereospecificity. No active site catalytic residue was revealed, and a structural water molecule was assumed to act as catalytic base in the retro-aldol cleavage reaction. Interestingly, the very large active site opening of E. coli TA suggests that a much larger molecule than L-threonine isomers may be easily accommodated, and threonine aldolases may actually play diverse physiological functions in different organisms. Substrate recognition and reaction specificity seem to be guided by the overall microenvironment that surrounds the substrate at the enzyme active site, rather than to one ore more specific residues. This article is protected by copyright. All rights reserved.

On the Catalytic Mechanism and Stereospecificity of Escherichia coli L-Threonine Aldolase.,di Salvo ML, Remesh SG, Vivoli M, Ghatge MS, Paiardini A, D'Aguanno S, Safo MK, Contestabile R FEBS J. 2013 Oct 25. doi: 10.1111/febs.12581. PMID:24165453<ref>PMID:24165453</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 4lnj" style="background-color:#fffaf0;"></div>

==See Also==
*[[Aldolase 3D structures|Aldolase 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Escherichia coli WV_060327]]
[[Category: Large Structures]]
[[Category: Contestabile R]]
[[Category: Remesh SG]]
[[Category: Safo MK]]