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== | ==CATALYTIC TRIMER OF ESCHERICHIA COLI ASPARTATE TRANSCARBAMOYLASE== | ||
<StructureSection load='3csu' size='340' side='right'caption='[[3csu]], [[Resolution|resolution]] 1.88Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[3csu]] is a 3 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=3CSU OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3CSU 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]] 1.88Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</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=3csu FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3csu OCA], [https://pdbe.org/3csu PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3csu RCSB], [https://www.ebi.ac.uk/pdbsum/3csu PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3csu ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/PYRB_ECOLI PYRB_ECOLI] | |||
== 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/cs/3csu_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=3csu ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The lack of knowledge of the three-dimensional structure of the trimeric, catalytic (C) subunit of aspartate transcarbamoylase (ATCase) has impeded understanding of the allosteric regulation of this enzyme and left unresolved the mechanism by which the active, unregulated C trimers are inactivated on incorporation into the unliganded (taut or T state) holoenzyme. Surprisingly, the isolated C trimer, based on the 1.9-A crystal structure reported here, resembles more closely the trimers in the T state enzyme than in the holoenzyme:bisubstrate-analog complex, which has been considered as the active, relaxed (R) state enzyme. Unlike the C trimer in either the T state or bisubstrate-analog-bound holoenzyme, the isolated C trimer lacks 3-fold symmetry, and the active sites are partially disordered. The flexibility of the C trimer, contrasted to the highly constrained T state ATCase, suggests that regulation of the holoenzyme involves modulating the potential for conformational changes essential for catalysis. Large differences in structure between the active C trimer and the holoenzyme:bisubstrate-analog complex call into question the view that this complex represents the activated R state of ATCase. | The lack of knowledge of the three-dimensional structure of the trimeric, catalytic (C) subunit of aspartate transcarbamoylase (ATCase) has impeded understanding of the allosteric regulation of this enzyme and left unresolved the mechanism by which the active, unregulated C trimers are inactivated on incorporation into the unliganded (taut or T state) holoenzyme. Surprisingly, the isolated C trimer, based on the 1.9-A crystal structure reported here, resembles more closely the trimers in the T state enzyme than in the holoenzyme:bisubstrate-analog complex, which has been considered as the active, relaxed (R) state enzyme. Unlike the C trimer in either the T state or bisubstrate-analog-bound holoenzyme, the isolated C trimer lacks 3-fold symmetry, and the active sites are partially disordered. The flexibility of the C trimer, contrasted to the highly constrained T state ATCase, suggests that regulation of the holoenzyme involves modulating the potential for conformational changes essential for catalysis. Large differences in structure between the active C trimer and the holoenzyme:bisubstrate-analog complex call into question the view that this complex represents the activated R state of ATCase. | ||
Assessment of the allosteric mechanism of aspartate transcarbamoylase based on the crystalline structure of the unregulated catalytic subunit.,Beernink PT, Endrizzi JA, Alber T, Schachman HK Proc Natl Acad Sci U S A. 1999 May 11;96(10):5388-93. PMID:10318893<ref>PMID:10318893</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 3csu" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Aspartate carbamoyltransferase 3D structures|Aspartate carbamoyltransferase 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Escherichia coli K-12]] | |||
[[Category: Large Structures]] | |||
[[Category: Alber T]] | |||
[[Category: Beernink PT]] | |||
[[Category: Endrizzi JA]] | |||
[[Category: Schachman HK]] | |||
Latest revision as of 15:33, 30 August 2023
CATALYTIC TRIMER OF ESCHERICHIA COLI ASPARTATE TRANSCARBAMOYLASECATALYTIC TRIMER OF ESCHERICHIA COLI ASPARTATE TRANSCARBAMOYLASE
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe lack of knowledge of the three-dimensional structure of the trimeric, catalytic (C) subunit of aspartate transcarbamoylase (ATCase) has impeded understanding of the allosteric regulation of this enzyme and left unresolved the mechanism by which the active, unregulated C trimers are inactivated on incorporation into the unliganded (taut or T state) holoenzyme. Surprisingly, the isolated C trimer, based on the 1.9-A crystal structure reported here, resembles more closely the trimers in the T state enzyme than in the holoenzyme:bisubstrate-analog complex, which has been considered as the active, relaxed (R) state enzyme. Unlike the C trimer in either the T state or bisubstrate-analog-bound holoenzyme, the isolated C trimer lacks 3-fold symmetry, and the active sites are partially disordered. The flexibility of the C trimer, contrasted to the highly constrained T state ATCase, suggests that regulation of the holoenzyme involves modulating the potential for conformational changes essential for catalysis. Large differences in structure between the active C trimer and the holoenzyme:bisubstrate-analog complex call into question the view that this complex represents the activated R state of ATCase. Assessment of the allosteric mechanism of aspartate transcarbamoylase based on the crystalline structure of the unregulated catalytic subunit.,Beernink PT, Endrizzi JA, Alber T, Schachman HK Proc Natl Acad Sci U S A. 1999 May 11;96(10):5388-93. PMID:10318893[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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