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==Crystal structure of the thymidylate synthase R166Q mutant== | |||
<StructureSection load='1fwm' size='340' side='right'caption='[[1fwm]], [[Resolution|resolution]] 2.20Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1fwm]] 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=1FWM OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1FWM 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]] 2.2Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CB3:10-PROPARGYL-5,8-DIDEAZAFOLIC+ACID'>CB3</scene>, <scene name='pdbligand=CXM:N-CARBOXYMETHIONINE'>CXM</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=1fwm FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1fwm OCA], [https://pdbe.org/1fwm PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1fwm RCSB], [https://www.ebi.ac.uk/pdbsum/1fwm PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1fwm 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/fw/1fwm_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=1fwm ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Thymidylate synthase (TS) catalyzes the folate-dependent methylation of deoxyuridine monophosphate (dUMP) to form thymidine monophosphate (dTMP). We have investigated the role of invariant arginine 166, one of four arginines that contact the dUMP phosphate, using site-directed mutagenesis, X-ray crystallography, and TS from Escherichia coli. The R166Q mutant was crystallized in the presence of dUMP and a structure determined to 2.9 A resolution, but neither the ligand nor the sulfate from the crystallization buffer was found in the active site. A second structure determined with crystals prepared in the presence of dUMP and the antifolate 10-propargyl-5,8-dideazafolate revealed that the inhibitor was bound in an extended, nonproductive conformation, partially occupying the nucleotide-binding site. A sulfate ion, rather than dUMP, was found in the nucleotide phosphate-binding site. Previous studies have shown that the substitution at three of the four arginines of the dUMP phosphate-binding site is permissive; however; for Arg166, all the mutations lead to a near-inactive mutant. The present structures of TS R166Q reveal that the phosphate-binding site is largely intact, but with a substantially reduced affinity for phosphate, despite the presence of the three remaining arginines. The position of Cys146, which initiates catalysis, is shifted in the mutant and resides in a position that interferes with the binding of the dUMP pyrimidine moiety. | |||
Crystal structures of thymidylate synthase mutant R166Q: structural basis for the nearly complete loss of catalytic activity.,Sotelo-Mundo RR, Changchien L, Maley F, Montfort WR J Biochem Mol Toxicol. 2006;20(2):88-92. PMID:16615077<ref>PMID:16615077</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1fwm" style="background-color:#fffaf0;"></div> | |||
== | ==See Also== | ||
Thymidylate synthase | *[[Thymidylate synthase 3D structures|Thymidylate synthase 3D structures]] | ||
== References == | |||
== | <references/> | ||
__TOC__ | |||
</StructureSection> | |||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Changchien L]] | |||
[[Category: Changchien | [[Category: Maley F]] | ||
[[Category: Maley | [[Category: Montfort WR]] | ||
[[Category: Montfort | [[Category: Sotelo-Mundo RR]] | ||
[[Category: Sotelo-Mundo | |||
Latest revision as of 07:32, 17 October 2024
Crystal structure of the thymidylate synthase R166Q mutantCrystal structure of the thymidylate synthase R166Q mutant
Structural highlights
FunctionTYSY_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 Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThymidylate synthase (TS) catalyzes the folate-dependent methylation of deoxyuridine monophosphate (dUMP) to form thymidine monophosphate (dTMP). We have investigated the role of invariant arginine 166, one of four arginines that contact the dUMP phosphate, using site-directed mutagenesis, X-ray crystallography, and TS from Escherichia coli. The R166Q mutant was crystallized in the presence of dUMP and a structure determined to 2.9 A resolution, but neither the ligand nor the sulfate from the crystallization buffer was found in the active site. A second structure determined with crystals prepared in the presence of dUMP and the antifolate 10-propargyl-5,8-dideazafolate revealed that the inhibitor was bound in an extended, nonproductive conformation, partially occupying the nucleotide-binding site. A sulfate ion, rather than dUMP, was found in the nucleotide phosphate-binding site. Previous studies have shown that the substitution at three of the four arginines of the dUMP phosphate-binding site is permissive; however; for Arg166, all the mutations lead to a near-inactive mutant. The present structures of TS R166Q reveal that the phosphate-binding site is largely intact, but with a substantially reduced affinity for phosphate, despite the presence of the three remaining arginines. The position of Cys146, which initiates catalysis, is shifted in the mutant and resides in a position that interferes with the binding of the dUMP pyrimidine moiety. Crystal structures of thymidylate synthase mutant R166Q: structural basis for the nearly complete loss of catalytic activity.,Sotelo-Mundo RR, Changchien L, Maley F, Montfort WR J Biochem Mol Toxicol. 2006;20(2):88-92. PMID:16615077[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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