View source for 1kzi


==Crystal Structure of EcTS/dUMP/THF Complex==
<StructureSection load='1kzi' size='340' side='right'caption='[[1kzi]], [[Resolution|resolution]] 1.75&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1kzi]] is a 2 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=1KZI OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1KZI 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]] 1.75&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CO3:CARBONATE+ION'>CO3</scene>, <scene name='pdbligand=CXM:N-CARBOXYMETHIONINE'>CXM</scene>, <scene name='pdbligand=DTT:2,3-DIHYDROXY-1,4-DITHIOBUTANE'>DTT</scene>, <scene name='pdbligand=DTU:(2R,3S)-1,4-DIMERCAPTOBUTANE-2,3-DIOL'>DTU</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=THG:(6S)-5,6,7,8-TETRAHYDROFOLATE'>THG</scene>, <scene name='pdbligand=UMP:2-DEOXYURIDINE+5-MONOPHOSPHATE'>UMP</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=1kzi FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1kzi OCA], [https://pdbe.org/1kzi PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1kzi RCSB], [https://www.ebi.ac.uk/pdbsum/1kzi PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1kzi ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/TYSY_ECOLI TYSY_ECOLI] Provides the sole de novo source of dTMP for DNA biosynthesis. This protein also binds to its mRNA thus repressing its own translation.
== 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/kz/1kzi_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=1kzi ConSurf].
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<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Mutant forms of thymidylate synthase (TS) with substitutions at the conserved active site residue, Trp 80, are deficient in the hydride transfer step of the TS reaction. These mutants produce a beta-mercaptoethanol (beta-ME) adduct of the 2'-deoxyuridine-5'-monophosphate (dUMP) exocyclic methylene intermediate. Trp 80 has been proposed to assist hydride transfer by stabilizing a 5,6,7,8-tetrahydrofolate (THF) radical cation intermediate [Barrett, J. E., Lucero, C. M., and Schultz, P. G. (1999) J. Am. Chem. Soc. 121, 7965-7966.] formed after THF changes its binding from the cofactor pocket to a putative alternate site. To understand the molecular basis of hydride transfer deficiency in a mutant in which Trp 80 was changed to Gly, we determined the X-ray structures of this mutant Escherichia coli TS complexed with dUMP and the folate analogue 10-propargyl-5,8-dideazafolate (CB3717) and of the wild-type enzyme complexed with dUMP and THF. The mutant enzyme has a cavity in the active site continuous with bulk solvent. This cavity, sealed from bulk solvent in wild-type TS by Leu 143, would allow nucleophilic attack of beta-ME on the dUMP C5 exocyclic methylene. The structure of the wild-type enzyme/dUMP/THF complex shows that THF is bound in the cofactor binding pocket and is well positioned to transfer hydride to the dUMP exocyclic methylene. Together, these results suggest that THF does not reorient during hydride transfer and indicate that the role of Trp 80 may be to orient Leu 143 to shield the active site from bulk solvent and to optimally position the cofactor for hydride transfer.

Tryptophan 80 and leucine 143 are critical for the hydride transfer step of thymidylate synthase by controlling active site access.,Fritz TA, Liu L, Finer-Moore JS, Stroud RM Biochemistry. 2002 Jun 4;41(22):7021-9. PMID:12033935<ref>PMID:12033935</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 1kzi" style="background-color:#fffaf0;"></div>

==See Also==
*[[Thymidylate synthase 3D structures|Thymidylate synthase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Finer-Moore JS]]
[[Category: Fritz TA]]
[[Category: Liu L]]
[[Category: Stroud RM]]