View source for 4tmk


==COMPLEX OF E. COLI THYMIDYLATE KINASE WITH THE BISUBSTRATE INHIBITOR TP5A==
<StructureSection load='4tmk' size='340' side='right'caption='[[4tmk]], [[Resolution|resolution]] 1.98&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4tmk]] 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=4TMK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4TMK 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]] 1.98&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=T5A:P1-(5-ADENOSYL)P5-(5-THYMIDYL)PENTAPHOSPHATE'>T5A</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=4tmk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4tmk OCA], [https://pdbe.org/4tmk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4tmk RCSB], [https://www.ebi.ac.uk/pdbsum/4tmk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4tmk ProSAT]</span></td></tr>
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== Function ==
[https://www.uniprot.org/uniprot/KTHY_ECOLI KTHY_ECOLI] Catalyzes the reversible phosphorylation of deoxythymidine monophosphate (dTMP) to deoxythymidine diphosphate (dTDP), using ATP as its preferred phosphoryl donor. Situated at the junction of both de novo and salvage pathways of deoxythymidine triphosphate (dTTP) synthesis, is essential for DNA synthesis and cellular growth.
== 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/tm/4tmk_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=4tmk ConSurf].
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== Publication Abstract from PubMed ==
The crystal structures of Escherichia coli thymidylate kinase (TmpK) in complex with P1-(5'-adenosyl)-P5-(5'-thymidyl)pentaphosphate and P1-(5'-adenosyl)P5-[5'-(3'-azido-3'-deoxythymidine)] pentaphosphate have been solved to 2.0-A and 2.2-A resolution, respectively. The overall structure of the bacterial TmpK is very similar to that of yeast TmpK. In contrast to the human and yeast TmpKs, which phosphorylate 3'-azido-3'-deoxythymidine 5'-monophosphate (AZT-MP) at a 200-fold reduced turnover number (kcat) in comparison to the physiological substrate dTMP, reduction of kcat is only 2-fold for the bacterial enzyme. The different kinetic properties toward AZT-MP between the eukaryotic TmpKs and E. coli TmpK can be rationalized by the different ways in which these enzymes stabilize the presumed transition state and the different manner in which a carboxylic acid side chain in the P loop interacts with the deoxyribose of the monophosphate. Yeast TmpK interacts with the 3'-hydroxyl of dTMP through Asp-14 of the P loop in a bidentate manner: binding of AZT-MP results in a shift of the P loop to accommodate the larger substituent. In E. coli TmpK, the corresponding residue is Glu-12, and it interacts in a side-on fashion with the 3'-hydroxyl of dTMP. This different mode of interaction between the P loop carboxylic acid with the 3' substituent of the monophosphate deoxyribose allows the accommodation of an azido group in the case of the E. coli enzyme without significant P loop movement. In addition, although the yeast enzyme uses Arg-15 (a glycine in E. coli) to stabilize the transition state, E. coli seems to use Arg-153 from a region termed Lid instead. Thus, the binding of AZT-MP to the yeast TmpK results in the shift of a catalytic residue, which is not the case for the bacterial kinase.

Structural basis for efficient phosphorylation of 3'-azidothymidine monophosphate by Escherichia coli thymidylate kinase.,Lavie A, Ostermann N, Brundiers R, Goody RS, Reinstein J, Konrad M, Schlichting I Proc Natl Acad Sci U S A. 1998 Nov 24;95(24):14045-50. PMID:9826650<ref>PMID:9826650</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Thymidylate kinase 3D structures|Thymidylate kinase 3D structures]]
*[[Thymidylate synthase 3D structures|Thymidylate synthase 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Lavie A]]
[[Category: Ostermann N]]
[[Category: Schlichting I]]