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New page: left|200px<br /><applet load="1xff" size="450" color="white" frame="true" align="right" spinBox="true" caption="1xff, resolution 1.80Å" /> '''Glutaminase domain o... |
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== | ==Glutaminase domain of glucosamine 6-phosphate synthase complexed with glutamate== | ||
BACKGROUND: Amidotransferases use the amide nitrogen of glutamine in a | <StructureSection load='1xff' size='340' side='right'caption='[[1xff]], [[Resolution|resolution]] 1.80Å' scene=''> | ||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1xff]] 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=1gdo 1gdo]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XFF OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1XFF 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]] 1.8Å</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=GLU:GLUTAMIC+ACID'>GLU</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=1xff FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1xff OCA], [https://pdbe.org/1xff PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1xff RCSB], [https://www.ebi.ac.uk/pdbsum/1xff PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1xff 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/1xff_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=1xff ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== 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®/PubMed®, a database of the U.S. National Library of Medicine.<br> | ||
</div> | |||
<div class="pdbe-citations 1xff" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Glucosamine 6-phosphate synthase|Glucosamine 6-phosphate synthase]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Isupov MN]] | |||
[[Category: Isupov | [[Category: Teplyakov A]] | ||
[[Category: Teplyakov | |||
Latest revision as of 09:44, 23 August 2023
Glutaminase domain of glucosamine 6-phosphate synthase complexed with glutamateGlutaminase domain of glucosamine 6-phosphate synthase complexed with glutamate
Structural highlights
FunctionGLMS_ECOLI Catalyzes the first step in hexosamine metabolism, converting fructose-6P into glucosamine-6P using glutamine as a nitrogen source. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedBACKGROUND: 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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