2aqx: Difference between revisions
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|PDB= 2aqx |SIZE=350|CAPTION= <scene name='initialview01'>2aqx</scene>, resolution 2.50Å | |PDB= 2aqx |SIZE=350|CAPTION= <scene name='initialview01'>2aqx</scene>, resolution 2.50Å | ||
|SITE= | |SITE= | ||
|LIGAND= <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene> and <scene name='pdbligand=ATP:ADENOSINE-5 | |LIGAND= <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene> and <scene name='pdbligand=ATP:ADENOSINE-5'-TRIPHOSPHATE'>ATP</scene> | ||
|ACTIVITY= [http://en.wikipedia.org/wiki/Inositol-trisphosphate_3-kinase Inositol-trisphosphate 3-kinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.1.127 2.7.1.127] | |ACTIVITY= [http://en.wikipedia.org/wiki/Inositol-trisphosphate_3-kinase Inositol-trisphosphate 3-kinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.1.127 2.7.1.127] | ||
|GENE= | |GENE= | ||
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[[Category: kinase]] | [[Category: kinase]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 23 14:39:14 2008'' | ||
Revision as of 12:39, 23 March 2008
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| 2aqx, resolution 2.50Å | |||||||||||||
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| Ligands: | MG and ATP | ||||||||||||
| Activity: | Inositol-trisphosphate 3-kinase, with EC number 2.7.1.127 | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
Crystal Structure of the Catalytic and CaM-Binding domains of Inositol 1,4,5-Trisphosphate 3-Kinase B
Overview
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.
About this Structure
2AQX is a Single protein structure of sequence from Mus musculus. Full crystallographic information is available from OCA.
Reference
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
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