View source for 4s2c


==Covalent complex of E. coli transaldolase TalB with fructose-6-phosphate==
<StructureSection load='4s2c' size='340' side='right'caption='[[4s2c]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4s2c]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4S2C OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4S2C 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]] 2.2&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=F6R:FRUCTOSE+-6-PHOSPHATE'>F6R</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=4s2c FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4s2c OCA], [https://pdbe.org/4s2c PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4s2c RCSB], [https://www.ebi.ac.uk/pdbsum/4s2c PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4s2c ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/TALB_ECOLI TALB_ECOLI] Transaldolase is important for the balance of metabolites in the pentose-phosphate pathway.[HAMAP-Rule:MF_00492]
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Transaldolase B (TalB) and D-fructose-6-phosphate aldolase A (FSAA) from Escherichia coli are C-C bond-forming enzymes. Using kinetic inhibition studies and mass spectrometry, it is shown that enzyme variants of FSAA and TalB that exhibit D-fructose-6-phosphate aldolase activity are inhibited covalently and irreversibly by D-tagatose 6-phosphate (D-T6P), whereas no inhibition was observed for wild-type transaldolase B from E. coli. The crystal structure of the variant TalB(F178Y) with bound sugar phosphate was solved to a resolution of 1.46 A and revealed a novel mode of covalent inhibition. The sugar is bound covalently via its C2 atom to the -NH2 group of the active-site residue Lys132. It is neither bound in the open-chain form nor as the closed-ring form of D-T6P, but has been converted to beta-D-galactofuranose 6-phosphate (D-G6P), a five-membered ring structure. The furanose ring of the covalent adduct is formed via a Heyns rearrangement and subsequent hemiacetal formation. This reaction is facilitated by Tyr178, which is proposed to act as acid-base catalyst. The crystal structure of the inhibitor complex is compared with the structure of the Schiff-base intermediate of TalB(E96Q) formed with the substrate D-fructose 6-phosphate determined to a resolution of 2.20 A. This comparison highlights the differences in stereochemistry at the C4 atom of the ligand as an essential determinant for the formation of the inhibitor adduct in the active site of the enzyme.

Novel mode of inhibition by D-tagatose 6-phosphate through a Heyns rearrangement in the active site of transaldolase B variants.,Stellmacher L, Sandalova T, Schneider S, Schneider G, Sprenger GA, Samland AK Acta Crystallogr D Struct Biol. 2016 Apr;72(Pt 4):467-76. doi:, 10.1107/S2059798316001170. Epub 2016 Mar 24. PMID:27050126<ref>PMID:27050126</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4s2c" style="background-color:#fffaf0;"></div>

==See Also==
*[[Transaldolase 3D structures|Transaldolase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli K-12]]
[[Category: Large Structures]]
[[Category: Samland AK]]
[[Category: Sandalova T]]
[[Category: Schneider G]]
[[Category: Sprenger GA]]
[[Category: Stellmacher L]]