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[[Image:1jqe.gif|left|200px]]<br /><applet load="1jqe" size="350" color="white" frame="true" align="right" spinBox="true"
caption="1jqe, resolution 1.91&Aring;" />
'''Crystal Structure Analysis of Human Histamine Methyltransferase (Ile105 Polymorphic Variant) Complexed with AdoHcy and Antimalarial Drug Quinacrine'''<br />


==Overview==
==Crystal Structure Analysis of Human Histamine Methyltransferase (Ile105 Polymorphic Variant) Complexed with AdoHcy and Antimalarial Drug Quinacrine==
BACKGROUND: Histamine plays important biological roles in cell-to-cell communication; it is a mediator in allergic responses, a regulator of gastric acid secretion, a messenger in bronchial asthma, and a neurotransmitter in the central nervous system. Histamine acts by binding to histamine receptors, and its local action is terminated primarily by methylation. Human histamine N-methyltransferase (HNMT) has a common polymorphism at residue 105 that correlates with the high- (Thr) and low- (Ile) activity phenotypes. RESULTS: Two ternary structures of human HNMT have been determined: the Thr105 variant complexed with its substrate histamine and reaction product AdoHcy and the Ile105 variant complexed with an inhibitor (quinacrine) and AdoHcy. Our steady-state kinetic data indicate that the recombinant Ile105 variant shows 1.8- and 1.3-fold increases in the apparent K(M) for AdoMet and histamine, respectively, and slightly (16%) but consistently lower specific activity as compared to that of the Thr105 variant. These differences hold over a temperature range of 25 degrees C-45 degrees C in vitro. Only at a temperature of 50 degrees C or higher is the Ile105 variant more thermolabile than the Thr105 enzyme. CONCLUSIONS: HNMT has a 2 domain structure including a consensus AdoMet binding domain, where the residue 105 is located on the surface, consistent with the kinetic data that the polymorphism does not affect overall protein stability at physiological temperatures but lowers K(M) values for AdoMet and histamine. The interactions between HNMT and quinacrine provide the first structural insights into a large group of pharmacologic HNMT inhibitors and their mechanisms of inhibition.
<StructureSection load='1jqe' size='340' side='right'caption='[[1jqe]], [[Resolution|resolution]] 1.91&Aring;' scene=''>
 
== Structural highlights ==
==Disease==
<table><tr><td colspan='2'>[[1jqe]] is a 2 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=1JQE OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1JQE FirstGlance]. <br>
Known disease associated with this structure: Asthma, susceptibility to OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=605238 605238]]
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.91&#8491;</td></tr>
 
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=QUN:QUINACRINE'>QUN</scene>, <scene name='pdbligand=SAH:S-ADENOSYL-L-HOMOCYSTEINE'>SAH</scene>, <scene name='pdbligand=UNX:UNKNOWN+ATOM+OR+ION'>UNX</scene></td></tr>
==About this Structure==
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1jqe FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1jqe OCA], [https://pdbe.org/1jqe PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1jqe RCSB], [https://www.ebi.ac.uk/pdbsum/1jqe PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1jqe ProSAT]</span></td></tr>
1JQE 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 <scene name='pdbligand=SAH:'>SAH</scene>, <scene name='pdbligand=QUN:'>QUN</scene> and <scene name='pdbligand=UNX:'>UNX</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Histamine_N-methyltransferase Histamine N-methyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.1.8 2.1.1.8] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JQE OCA].
</table>
 
== Function ==
==Reference==
[https://www.uniprot.org/uniprot/HNMT_HUMAN HNMT_HUMAN] Inactivates histamine by N-methylation. Plays an important role in degrading histamine and in regulating the airway response to histamine.
Two polymorphic forms of human histamine methyltransferase: structural, thermal, and kinetic comparisons., Horton JR, Sawada K, Nishibori M, Zhang X, Cheng X, Structure. 2001 Sep;9(9):837-49. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11566133 11566133]
== Evolutionary Conservation ==
[[Category: Histamine N-methyltransferase]]
[[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/jq/1jqe_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=1jqe ConSurf].
<div style="clear:both"></div>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Homo sapiens]]
[[Category: Single protein]]
[[Category: Large Structures]]
[[Category: Cheng, X.]]
[[Category: Cheng X]]
[[Category: Horton, J R.]]
[[Category: Horton JR]]
[[Category: Nishibori, M.]]
[[Category: Nishibori M]]
[[Category: Sawada, K.]]
[[Category: Sawada K]]
[[Category: Zhang, X.]]
[[Category: Zhang X]]
[[Category: QUN]]
[[Category: SAH]]
[[Category: UNX]]
[[Category: classic methyltransferase fold]]
[[Category: polymorphic variant]]
[[Category: protein-substrate-cofactor complex]]
 
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:25:32 2008''

Latest revision as of 10:41, 7 February 2024

Crystal Structure Analysis of Human Histamine Methyltransferase (Ile105 Polymorphic Variant) Complexed with AdoHcy and Antimalarial Drug QuinacrineCrystal Structure Analysis of Human Histamine Methyltransferase (Ile105 Polymorphic Variant) Complexed with AdoHcy and Antimalarial Drug Quinacrine

Structural highlights

1jqe is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 1.91Å
Ligands:, ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

HNMT_HUMAN Inactivates histamine by N-methylation. Plays an important role in degrading histamine and in regulating the airway response to histamine.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

1jqe, resolution 1.91Å

Drag the structure with the mouse to rotate

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