View source for 1rak


==Bacterial cytosine deaminase D314S mutant bound to 5-fluoro-4-(S)-hydroxyl-3,4-dihydropyrimidine.==
<StructureSection load='1rak' size='340' side='right'caption='[[1rak]], [[Resolution|resolution]] 1.32&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1rak]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RAK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1RAK 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]] 1.32&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FE:FE+(III)+ION'>FE</scene>, <scene name='pdbligand=FPY:(4S)-5-FLUORO-4-HYDROXY-3,4-DIHYDROPYRIMIDIN-2(1H)-ONE'>FPY</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</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=1rak FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1rak OCA], [https://pdbe.org/1rak PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1rak RCSB], [https://www.ebi.ac.uk/pdbsum/1rak PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1rak ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CODA_ECOLI CODA_ECOLI] 
== 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/ra/1rak_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=1rak ConSurf].
<div style="clear:both"></div>
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== Publication Abstract from PubMed ==
Cytosine deaminase (CD) is currently being used as a suicide gene for cancer gene therapy. The premise of this therapy is the preferential deamination of 5-fluorocytosine (5FC) to 5-fluorouracil by cancer cells expressing cytosine deaminase. However, a lack of efficient gene transfer to tumors combined with inefficient 5FC turnover currently limits the clinical applications of this gene therapy approach. We have used random mutagenesis to create novel bacterial cytosine deaminases that demonstrate an increased preference for 5FC over cytosine. Among the 15 mutants isolated, one conferred sensitivity to Escherichia coli in a negative selection system at a concentration of 5FC that was 10-fold lower than a sublethal dose for wild-type CD. Evaluation of individual substitutions found in this double mutant (Q102R, D314G) demonstrated that the substitution at residue D314 was solely responsible for the observed increase in sensitivity to 5FC. Additional mutagenesis at D314 resulted in the identification of two more substitutions with the ability to confer enhanced 5FC sensitivity to E.coli. Structure determinations of the three CD variants in the presence and absence of a transition state 5FC analogue provide insights to the determinants of substrate binding specificity at the 5' position of the pyrimidine ring. CD mutant D314A is a promising candidate for further gene therapy studies.

Random mutagenesis and selection of Escherichia coli cytosine deaminase for cancer gene therapy.,Mahan SD, Ireton GC, Knoeber C, Stoddard BL, Black ME Protein Eng Des Sel. 2004 Aug;17(8):625-33. Epub 2004 Sep 20. PMID:15381761<ref>PMID:15381761</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1rak" style="background-color:#fffaf0;"></div>

==See Also==
*[[Deaminase 3D structures|Deaminase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Black ME]]
[[Category: Ireton GC]]
[[Category: Mahan SD]]
[[Category: Stoddard BL]]