1fkw: Difference between revisions

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OCA

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-[[Image:1fkw.gif|left|200px]]<br /><applet load="1fkw" size="450" color="white" frame="true" align="right" spinBox="true"
-caption="1fkw, resolution 2.4&Aring;" />
-'''MURINE ADENOSINE DEAMINASE (D295E)'''<br />
-==Overview==
+==MURINE ADENOSINE DEAMINASE (D295E)==
-Two adjacent aspartates, Asp 295 and Asp 296, playing major roles in the, reaction catalyzed by mouse adenosine deaminase (mADA) were altered using, site-directed mutagenesis. These mutants were expressed and purified from, an ADA-deficient bacterial strain and characterized. Circular dichroism, spectroscopy shows the mutants to have unperturbed secondary structure., Their zinc content compares well to that of wild-type enzyme. Changing Asp, 295 to a glutamate decreases the kcat but does not alter the Km for, adenosine, confirming the importance of this residue in the catalytic, process and its minimal role in substrate binding. The crystal structure, of the D295E mutant reveals a displacement of the catalytic water from the, active site due to the longer glutamate side chain, resulting in the, mutant's inability to turn over the substrate. In contrast, Asp 296, mutants exhibit markedly increased Km values, establishing this residue's, critical role in substrate binding. The Asp 296-&gt;Ala mutation causes a, 70-fold increase in the Km for adenosine and retains 0.001% of the, wild-type kcat/Km value, whereas the ASP 296-&gt;Asn mutant has a 10-fold, higher Km and retains 1% of the wild-type kcat/Km value. The structure of, the D296A mutant shows that the impaired binding of substrate is caused by, the loss of a single hydrogen bond between a carboxylate oxygen and N7 of, the purine ring. These results and others discussed below are in agreement, with the postulated role of the adjacent aspartates in the catalytic, mechanism for mADA.
+<StructureSection load='1fkw' size='340' side='right'caption='[[1fkw]], [[Resolution|resolution]] 2.40&Aring;' scene=''>
+== Structural highlights ==
+<table><tr><td colspan='2'>[[1fkw]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Mus_musculus Mus musculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1FKW OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1FKW 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]] 2.4&#8491;</td></tr>
+<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=PUR:PURINE+RIBOSIDE'>PUR</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</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=1fkw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1fkw OCA], [https://pdbe.org/1fkw PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1fkw RCSB], [https://www.ebi.ac.uk/pdbsum/1fkw PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1fkw ProSAT]</span></td></tr>
+</table>
+== Function ==
+[https://www.uniprot.org/uniprot/ADA_MOUSE ADA_MOUSE] Catalyzes the hydrolytic deamination of adenosine and 2-deoxyadenosine. Plays an important role in purine metabolism and in adenosine homeostasis. Modulates signaling by extracellular adenosine, and so contributes indirectly to cellular signaling events. Acts as a positive regulator of T-cell coactivation, by binding DPP4. Its interaction with DPP4 regulates lymphocyte-epithelial cell adhesion (By similarity).
+== 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/fk/1fkw_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=1fkw ConSurf].
+<div style="clear:both"></div>
-==About this Structure==
+==See Also==
-FKW is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mus_musculus Mus musculus] with ZN and PUR as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Adenosine_deaminase Adenosine deaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.4.4 3.5.4.4] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1FKW OCA].
+*[[Adenosine deaminase 3D structures|Adenosine deaminase 3D structures]]
+__TOC__
-==Reference==
+</StructureSection>
-Probing the functional role of two conserved active site aspartates in mouse adenosine deaminase., Sideraki V, Mohamedali KA, Wilson DK, Chang Z, Kellems RE, Quiocho FA, Rudolph FB, Biochemistry. 1996 Jun 18;35(24):7862-72. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=8672487 8672487]
+[[Category: Large Structures]]
-[[Category: Adenosine deaminase]]
 [[Category: Mus musculus]]
-[[Category: Single protein]]
+[[Category: Quiocho FA]]
-[[Category: Quiocho, F.A.]]
+[[Category: Wilson DK]]
-[[Category: Wilson, D.K.]]
-[[Category: PUR]]
-[[Category: ZN]]
-[[Category: aminohydrolase]]
-[[Category: tim barrel]]
-[[Category: zinc cofactor]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 15:00:38 2007''