1z2n

<table><tr><td colspan='2'>[[1z2n]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Entamoeba_histolytica_hm-1:imss Entamoeba histolytica hm-1:imss]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Z2N OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1Z2N FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ADP:ADENOSINE-5-DIPHOSPHATE'>ADP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</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;'>[[1z2o|1z2o]], [[1z2p|1z2p]]</div></td></tr>

[[https://www.uniprot.org/uniprot/ITPK1_ENTHI ITPK1_ENTHI]] Kinase that can phosphorylate various inositol polyphosphate such as Ins(3,4,5,6)P4 or Ins(1,3,4)P3. Phosphorylates Ins(3,4,5,6)P4 at position 1 to form Ins(1,3,4,5,6)P5. This reaction is thought to have regulatory importance, since Ins(3,4,5,6)P4 is an inhibitor of plasma membrane Ca(2+)-activated Cl(-) channels, while Ins(1,3,4,5,6)P5 is not. Also phosphorylates Ins(1,3,4)P3 on O-5 and O-6 to form Ins(1,3,4,6)P4, an essential molecule in the hexakisphosphate (InsP6) pathway. May also act as an isomerase that interconverts the inositol tetrakisphosphate isomers Ins(1,3,4,5)P4 and Ins(1,3,4,6)P4 in the presence of ADP and magnesium.

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== Publication Abstract from PubMed ==

Inositol hexakisphosphate and other inositol high polyphosphates have diverse and critical roles in eukaryotic regulatory pathways. Inositol 1,3,4-trisphosphate 5/6-kinase catalyzes the rate-limiting step in inositol high polyphosphate synthesis in animals. This multifunctional enzyme also has inositol 3,4,5,6-tetrakisphosphate 1-kinase and other activities. The structure of an archetypal family member, from Entamoeba histolytica, has been determined to 1.2 A resolution in binary and ternary complexes with nucleotide, substrate, and product. The structure reveals an ATP-grasp fold. The inositol ring faces ATP edge-on such that the 5- and 6-hydroxyl groups are nearly equidistant from the ATP gamma-phosphate in catalytically productive phosphoacceptor positions and explains the unusual dual site specificity of this kinase. Inositol tris- and tetrakisphosphates interact via three phosphate binding subsites and one solvent-exposed site that could in principle be occupied by 18 different substrates, explaining the mechanisms for the multiple specificities and catalytic activities of this enzyme.

Specificity determinants in inositol polyphosphate synthesis: crystal structure of inositol 1,3,4-trisphosphate 5/6-kinase.,Miller GJ, Wilson MP, Majerus PW, Hurley JH Mol Cell. 2005 Apr 15;18(2):201-12. PMID:15837423<ref>PMID:15837423</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

<references/>

[[Category: Entamoeba histolytica hm-1:imss]]

[[Category: Hurley, J H]]

[[Category: Majerus, P W]]

[[Category: Miller, G J]]

[[Category: Wilson, M P]]

[[Category: Transferase]]