2aqx

<table><tr><td colspan='2'>[[2aqx]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Lk3_transgenic_mice Lk3 transgenic mice]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2AQX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2AQX FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ATP:ADENOSINE-5-TRIPHOSPHATE'>ATP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Inositol-trisphosphate_3-kinase Inositol-trisphosphate 3-kinase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.1.127 2.7.1.127] </span></td></tr>

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== Publication Abstract from PubMed ==

D-Myoinositol 1,4,5-trisphophate 3-kinases (IP(3)-3Ks) play important roles in metazoan cellular signaling. It has been demonstrated that mice without a functional version of IP(3)-3K isoform B are deficient in peripheral T-cells, indicating that IP(3)-3KB is essential to the developing immune system. The recent apo IP(3)-3KA structure exhibited a helix at the catalytic domain N-terminus exhibited a helix at the N-terminus of the catalytic domain, with a tryptophan indole moiety mimicking the binding mode of the substrate ATP purine ring, suggesting a mechanism of autoinhibition. Here we present the structure of the complete catalytic domain of IP(3)-3KB, including the CaM binding domain in complex with Mg(2+) and ATP. The crystal structure reveals a homodimeric arrangement of IP(3)-3KB catalytic domains, mediated via an intermolecular antiparallel beta-sheet formed from part of the CaM binding region. Residues from the putative autoinhibitory helix are rearranged into a loop configuration, with extensive interactions with the bound ATP. Mutagenesis of residues from this region reveals that substitution of the putative autoinhibitory tryptophan generates a hyperactive enzyme which retains Ca(2+)/CaM sensitivity. The IP(3)-3KB structure suggests a mechanism of enzyme activation, and raises the possibility that an interaction between IP(3)-3KB molecules may occur as part of the catalytic or regulatory cycle.

Structural insights into enzyme regulation for inositol 1,4,5-trisphosphate 3-kinase B.,Chamberlain PP, Sandberg ML, Sauer K, Cooke MP, Lesley SA, Spraggon G Biochemistry. 2005 Nov 8;44(44):14486-93. PMID:16262249<ref>PMID:16262249</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 2aqx" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Inositol-trisphosphate 3-kinase]]

[[Category: Lk3 transgenic mice]]

[[Category: Chamberlain, P P]]

[[Category: Cooke, M P]]

[[Category: Lesley, S A]]

[[Category: Sandberg, M L]]

[[Category: Sauer, K]]

[[Category: Spraggon, G]]

[[Category: Transferase]]