1kfk

<table><tr><td colspan='2'>[[1kfk]] 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=1KFK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1KFK 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='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[1bks|1bks]]</div></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>

[[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.

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== 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>

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<div class="pdbe-citations 1kfk" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Salty]]

[[Category: Tryptophan synthase]]

[[Category: Arac, D]]

[[Category: Dunn, M F]]

[[Category: Kulik, V]]

[[Category: Niks, D]]

[[Category: Schlichting, I]]

[[Category: Seidel, R]]

[[Category: Weyand, M]]

[[Category: Tryptophan biosynthesis]]