View source for 1xfg


==Glutaminase domain of glucosamine 6-phosphate synthase complexed with l-glu hydroxamate==
<StructureSection load='1xfg' size='340' side='right'caption='[[1xfg]], [[Resolution|resolution]] 1.85&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1xfg]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=1gms 1gms]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XFG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1XFG 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]] 1.85&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=HGA:GLUTAMINE+HYDROXAMATE'>HGA</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</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=1xfg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1xfg OCA], [https://pdbe.org/1xfg PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1xfg RCSB], [https://www.ebi.ac.uk/pdbsum/1xfg PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1xfg ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/GLMS_ECOLI GLMS_ECOLI] Catalyzes the first step in hexosamine metabolism, converting fructose-6P into glucosamine-6P using glutamine as a nitrogen source.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/xf/1xfg_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1xfg ConSurf].
<div style="clear:both"></div>
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== Publication Abstract from PubMed ==
BACKGROUND: Amidotransferases use the amide nitrogen of glutamine in a number of important biosynthetic reactions. They are composed of a glutaminase domain, which catalyzes the hydrolysis of glutamine to glutamate and ammonia, and a synthetase domain, catalyzing amination of the substrate. To gain insight into the mechanism of nitrogen transfer, we examined the structure of the glutaminase domain of glucosamine 6-phosphate synthase (GLMS). RESULTS: The crystal structures of the enzyme complexed with glutamate and with a competitive inhibitor, Glu-hydroxamate, have been determined to 1.8 A resolution. The protein fold has structural homology to other members of the superfamily of N-terminal nucleophile (Ntn) hydrolases, being a sandwich of antiparallel beta sheets surrounded by two layers of alpha helices. CONCLUSIONS: The structural homology between the glutaminase domain of GLMS and that of PRPP amidotransferase (the only other Ntn amidotransferase whose structure is known) indicates that they may have diverged from a common ancestor. Cys1 is the catalytic nucleophile in GLMS, and the nucleophilic character of its thiol group appears to be increased through general base activation by its own alpha-amino group. Cys1 can adopt two conformations, one active and one inactive; glutamine binding locks the residue in a predetermined conformation. We propose that when a nitrogen acceptor is present Cys1 is kept in the active conformation, explaining the phenomenon of substrate-induced activation of the enzyme, and that Arg26 is central in this coupling.

Substrate binding is required for assembly of the active conformation of the catalytic site in Ntn amidotransferases: evidence from the 1.8 A crystal structure of the glutaminase domain of glucosamine 6-phosphate synthase.,Isupov MN, Obmolova G, Butterworth S, Badet-Denisot MA, Badet B, Polikarpov I, Littlechild JA, Teplyakov A Structure. 1996 Jul 15;4(7):801-10. PMID:8805567<ref>PMID:8805567</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 1xfg" style="background-color:#fffaf0;"></div>

==See Also==
*[[Glucosamine 6-phosphate synthase|Glucosamine 6-phosphate synthase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Isupov MN]]
[[Category: Teplyakov A]]