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== | ==Bacillus subtilis cytidine deaminase with an Arg56 - Ala substitution== | ||
The zinc-containing cytidine deaminase (CDA, EC 3.5.4.5) is a pyrimidine | <StructureSection load='1uwz' size='340' side='right'caption='[[1uwz]], [[Resolution|resolution]] 1.99Å' scene=''> | ||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1uwz]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacillus_subtilis Bacillus subtilis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1UWZ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1UWZ 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]] 1.99Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=THU:TETRAHYDRODEOXYURIDINE'>THU</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=1uwz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1uwz OCA], [https://pdbe.org/1uwz PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1uwz RCSB], [https://www.ebi.ac.uk/pdbsum/1uwz PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1uwz ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/CDD_BACSU CDD_BACSU] This enzyme scavenges exogenous and endogenous cytidine and 2'-deoxycytidine for UMP synthesis. | |||
== 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/uw/1uwz_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=1uwz ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The zinc-containing cytidine deaminase (CDA, EC 3.5.4.5) is a pyrimidine salvage enzyme catalyzing the hydrolytic deamination of cytidine and 2'-deoxycytidine forming uridine and 2'-deoxyuridine, respectively. Homodimeric CDA (D-CDA) and homotetrameric CDA (T-CDA) both contain one zinc ion per subunit coordinated to the catalytic water molecule. The zinc ligands in D-CDA are one histidine and two cysteine residues, whereas in T-CDA zinc is coordinated to three cysteines. Two of the zinc coordinating cysteines in T-CDA form hydrogen bonds to the conserved residue Arg56, and this residue together with the dipole moments from two alpha-helices partially neutralizes the additional negative charge in the active site, leading to a catalytic activity similar to D-CDA. Arg56 has been substituted by a glutamine (R56Q), the corresponding residue in D-CDA, an alanine (R56A), and an aspartate (R56D). Moreover, one of the zinc-liganding cysteines has been substituted by histidine to mimic D-CDA, alone (C53H) and in combination with R56Q (C53H/R56Q). R56A, R56Q, and C53H/R56Q contain the same amount of zinc as the wild-type enzyme. The zinc-binding capacity of R56D is reduced. Only R56A, R56Q, and C53H/R56Q yielded measurable CDA activity, R56A and R56Q with similar K(m) but decreased V(max) values compared to wild-type enzyme. Because of dissociation into its inactive subunits, it was impossible to determine the kinetic parameters for C53H/R56Q. R56A and C53H/R56Q display increased apparent pK(a) values compared to the wild-type enzyme and R56Q. On the basis of the structures of R56A, R56Q, and C53H/R56Q an explanation is provided of kinetic results and the apparent instability of C53H/R56Q. | |||
Structural, kinetic, and mutational studies of the zinc ion environment in tetrameric cytidine deaminase.,Johansson E, Neuhard J, Willemoes M, Larsen S Biochemistry. 2004 May 25;43(20):6020-9. PMID:15147186<ref>PMID:15147186</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1uwz" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Deaminase 3D structures|Deaminase 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Bacillus subtilis]] | [[Category: Bacillus subtilis]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Johansson E]] | |||
[[Category: Johansson | [[Category: Larsen S]] | ||
[[Category: Larsen | [[Category: Neuhard J]] | ||
[[Category: Neuhard | [[Category: Willemoes M]] | ||
[[Category: Willemoes | |||