View source for 1k8x


==Crystal Structure Of AlphaT183V Mutant Of Tryptophan Synthase From Salmonella Typhimurium==
<StructureSection load='1k8x' size='340' side='right'caption='[[1k8x]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1k8x]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/ ] and [https://en.wikipedia.org/wiki/Salty Salty]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1K8X OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1K8X FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=PLP:PYRIDOXAL-5-PHOSPHATE'>PLP</scene></td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Tryptophan_synthase Tryptophan synthase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.1.20 4.2.1.20] </span></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=1k8x FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1k8x OCA], [https://pdbe.org/1k8x PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1k8x RCSB], [https://www.ebi.ac.uk/pdbsum/1k8x PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1k8x ProSAT]</span></td></tr>
</table>
== Function ==
[[https://www.uniprot.org/uniprot/TRPA_SALTY TRPA_SALTY]] The alpha subunit is responsible for the aldol cleavage of indoleglycerol phosphate to indole and glyceraldehyde 3-phosphate. [[https://www.uniprot.org/uniprot/TRPB_SALTY TRPB_SALTY]] The beta subunit is responsible for the synthesis of L-tryptophan from indole and L-serine. 
== 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/k8/1k8x_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=1k8x ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The catalytic activity and substrate channeling of the pyridoxal 5'-phosphate-dependent tryptophan synthase alpha(2)beta(2) complex is regulated by allosteric interactions that modulate the switching of the enzyme between open, low activity and closed, high activity states during the catalytic cycle. The highly conserved alphaThr183 residue is part of loop alphaL6 and is located next to the alpha-active site and forms part of the alpha-beta subunit interface. The role of the interactions of alphaThr183 in alpha-site catalysis and allosteric regulation was investigated by analyzing the kinetics and crystal structures of the isosteric mutant alphaThr183Val. The mutant displays strongly impaired allosteric alpha-beta communication, and the catalytic activity of the alpha-reaction is reduced one hundred fold, whereas the beta-activity is not affected. The structural work establishes that the basis for the missing inter-subunit signaling is the lack of loop alphaL6 closure even in the presence of the alpha-subunit ligands, 3-indolyl-D-glycerol 3'-phosphate, or 3-indolylpropanol 3'-phosphate. The structural basis for the reduced alpha-activity has its origins in the missing hydrogen bond between alphaThr183 and the catalytic residue, alphaAsp60.

On the role of alphaThr183 in the allosteric regulation and catalytic mechanism of tryptophan synthase.,Kulik V, Weyand M, Seidel R, Niks D, Arac D, Dunn MF, Schlichting I J Mol Biol. 2002 Dec 6;324(4):677-90. PMID:12460570<ref>PMID:12460570</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 1k8x" style="background-color:#fffaf0;"></div>

==See Also==
*[[Tryptophan synthase 3D structures|Tryptophan synthase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Salty]]
[[Category: Tryptophan synthase]]
[[Category: Arac, D]]
[[Category: Dunn, M F]]
[[Category: Kulik, V]]
[[Category: Niks, D]]
[[Category: Schlichting, I]]
[[Category: Siedel, R]]
[[Category: Weyand, M]]
[[Category: Helix]]
[[Category: Lyase]]