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==Crystal structure of UDP-GlcNAc 2-epimerase from Neisseria meningitidis bound to UDP-GlcNAc==
<StructureSection load='6vlc' size='340' side='right'caption='[[6vlc]], [[Resolution|resolution]] 2.15&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6vlc]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Neisseria_meningitidis_Z2491 Neisseria meningitidis Z2491]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6VLC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6VLC 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]] 2.15&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=UD1:URIDINE-DIPHOSPHATE-N-ACETYLGLUCOSAMINE'>UD1</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=6vlc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6vlc OCA], [https://pdbe.org/6vlc PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6vlc RCSB], [https://www.ebi.ac.uk/pdbsum/6vlc PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6vlc ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/SACA_NEIMA SACA_NEIMA] Catalyzes the interconversion between UDP-N-acetylglucosamine (UDP-GlcNAc) and UDP-N-acetylmannosamine (UDP-ManNAc). Involved in the biosynthesis of the capsular polysaccharides. In vitro, can also use several chemoenzymatically synthesized UDP-ManNAc derivatives as substrates, with lower efficiency.<ref>PMID:26598987</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Bacterial nonhydrolyzing UDP-N-acetylglucosamine 2-epimerases catalyze the reversible interconversion of UDP-N-acetylglucosamine (UDP-GlcNAc) and UDP-N-acetylmannosamine (UDP-ManNAc). UDP-ManNAc is an important intermediate in the biosynthesis of certain cell-surface polysaccharides, including those in some pathogenic bacteria, such as Neisseria meningitidis and Streptococcus pneumoniae. Many of these epimerases are allosterically regulated by UDP-GlcNAc, which binds adjacent to the active site and is required to initiate UDP-ManNAc epimerization. Here, two crystal structures of UDP-N-acetylglucosamine 2-epimerase from Neisseria meningitidis serogroup A (NmSacA) are presented. One crystal structure is of the substrate-free enzyme, while the other structure contains UDP-GlcNAc substrate bound to the active site. Both structures form dimers as seen in similar epimerases, and substrate binding to the active site induces a large conformational change in which two Rossmann-like domains clamp down on the substrate. Unlike other epimerases, NmSacA does not require UDP-GlcNAc to instigate the epimerization of UDP-ManNAc, although UDP-GlcNAc was found to enhance the rate of epimerization. In spite of the conservation of residues involved in binding the allosteric UDP-GlcNAc observed in similar UDP-GlcNAc 2-epimerases, the structures presented here do not contain UDP-GlcNAc bound in the allosteric site. These structural results provide additional insight into the mechanism and regulation of this critical enzyme and improve the structural understanding of the ability of NmSacA to epimerize modified substrates.

Structural characterization of a nonhydrolyzing UDP-GlcNAc 2-epimerase from Neisseria meningitidis serogroup A.,Hurlburt NK, Guan J, Ong H, Yu H, Chen X, Fisher AJ Acta Crystallogr F Struct Biol Commun. 2020 Nov 1;76(Pt 11):557-567. doi:, 10.1107/S2053230X20013680. Epub 2020 Oct 29. PMID:33135674<ref>PMID:33135674</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6vlc" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Neisseria meningitidis Z2491]]
[[Category: Fisher AJ]]
[[Category: Hurlburt NK]]