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[[Image:1hkc.gif|left|200px]]<br />
<applet load="1hkc" size="450" color="white" frame="true" align="right" spinBox="true"
caption="1hkc, resolution 2.80&Aring;" />
'''RECOMBINANT HUMAN HEXOKINASE TYPE I COMPLEXED WITH GLUCOSE AND PHOSPHATE'''<br />


==Overview==
==RECOMBINANT HUMAN HEXOKINASE TYPE I COMPLEXED WITH GLUCOSE AND PHOSPHATE==
Hexokinase I, the pacemaker of glycolysis in brain tissue and red blood, cells, is comprised of two similar domains fused into a single polypeptide, chain. The C-terminal half of hexokinase I is catalytically active, whereas the N-terminal half is necessary for the relief of product, inhibition by phosphate. A crystalline complex of recombinant human, hexokinase I with glucose and phosphate (2.8 A resolution) reveals a, single binding site for phosphate and glucose at the N-terminal half of, the enzyme. Glucose and phosphate stabilize the N-terminal half in a, closed conformation. Unexpectedly, glucose binds weakly to the C-terminal, half of the enzyme and does not by itself stabilize a closed conformation., Evidently a stable, closed C-terminal half requires either ATP or glucose, 6-phosphate along with glucose. The crystal structure here, in conjunction, with other studies in crystallography and directed mutation, puts the, phosphate regulatory site at the N-terminal half, the site of potent, product inhibition at the C-terminal half, and a secondary site for the, weak interaction of glucose 6-phosphate at the N-terminal half of the, enzyme. The relevance of crystal structures of hexokinase I to the, properties of monomeric hexokinase I and oligomers of hexokinase I bound, to the surface of mitochondria is discussed.
<StructureSection load='1hkc' size='340' side='right'caption='[[1hkc]], [[Resolution|resolution]] 2.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1hkc]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HKC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1HKC FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BGC:BETA-D-GLUCOSE'>BGC</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</scene>, <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</scene></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=1hkc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1hkc OCA], [https://pdbe.org/1hkc PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1hkc RCSB], [https://www.ebi.ac.uk/pdbsum/1hkc PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1hkc ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/HXK1_HUMAN HXK1_HUMAN] Defects in HK1 are the cause of hexokinase deficiency (HK deficiency) [MIM:[https://omim.org/entry/235700 235700]. HK deficiency is a rare autosomal recessive disease with nonspherocytic hemolytic anemia as the predominant clinical feature.
== Function ==
[https://www.uniprot.org/uniprot/HXK1_HUMAN HXK1_HUMAN]
== 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/hk/1hkc_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=1hkc ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Hexokinase I, the pacemaker of glycolysis in brain tissue and red blood cells, is comprised of two similar domains fused into a single polypeptide chain. The C-terminal half of hexokinase I is catalytically active, whereas the N-terminal half is necessary for the relief of product inhibition by phosphate. A crystalline complex of recombinant human hexokinase I with glucose and phosphate (2.8 A resolution) reveals a single binding site for phosphate and glucose at the N-terminal half of the enzyme. Glucose and phosphate stabilize the N-terminal half in a closed conformation. Unexpectedly, glucose binds weakly to the C-terminal half of the enzyme and does not by itself stabilize a closed conformation. Evidently a stable, closed C-terminal half requires either ATP or glucose 6-phosphate along with glucose. The crystal structure here, in conjunction with other studies in crystallography and directed mutation, puts the phosphate regulatory site at the N-terminal half, the site of potent product inhibition at the C-terminal half, and a secondary site for the weak interaction of glucose 6-phosphate at the N-terminal half of the enzyme. The relevance of crystal structures of hexokinase I to the properties of monomeric hexokinase I and oligomers of hexokinase I bound to the surface of mitochondria is discussed.


==Disease==
Regulation of hexokinase I: crystal structure of recombinant human brain hexokinase complexed with glucose and phosphate.,Aleshin AE, Zeng C, Bartunik HD, Fromm HJ, Honzatko RB J Mol Biol. 1998 Sep 18;282(2):345-57. PMID:9735292<ref>PMID:9735292</ref>
Known disease associated with this structure: Hemolytic anemia due to hexokinase deficiency OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=142600 142600]]


==About this Structure==
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
1HKC is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with GLC, PO4 and K as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Hexokinase Hexokinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.1.1 2.7.1.1] Structure known Active Sites: GLN, MEC, MEN, PIC and PIN. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1HKC OCA].
</div>
<div class="pdbe-citations 1hkc" style="background-color:#fffaf0;"></div>


==Reference==
==See Also==
Regulation of hexokinase I: crystal structure of recombinant human brain hexokinase complexed with glucose and phosphate., Aleshin AE, Zeng C, Bartunik HD, Fromm HJ, Honzatko RB, J Mol Biol. 1998 Sep 18;282(2):345-57. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=9735292 9735292]
*[[Hexokinase 3D structures|Hexokinase 3D structures]]
[[Category: Hexokinase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Homo sapiens]]
[[Category: Single protein]]
[[Category: Large Structures]]
[[Category: Aleshin, A.E.]]
[[Category: Aleshin AE]]
[[Category: Honzatko, R.B.]]
[[Category: Honzatko RB]]
[[Category: GLC]]
[[Category: K]]
[[Category: PO4]]
[[Category: allosteric enzyme]]
[[Category: glucose]]
[[Category: glycolysis]]
[[Category: phosphate]]
[[Category: phosphotransferase]]
 
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