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==CRYSTAL STRUCTURE OF THYMIDYLATE SYNTHASE R126E MUTANT== | |||
<StructureSection load='1ajm' size='340' side='right'caption='[[1ajm]], [[Resolution|resolution]] 2.40Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1ajm]] 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=1AJM OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1AJM 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]] 2.4Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CXM:N-CARBOXYMETHIONINE'>CXM</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=1ajm FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ajm OCA], [https://pdbe.org/1ajm PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ajm RCSB], [https://www.ebi.ac.uk/pdbsum/1ajm PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ajm 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/aj/1ajm_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=1ajm ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Thymidylate synthase (TS) is a long-standing target for anticancer drugs and is of interest for its rich mechanistic features. The enzyme catalyzes the conversion of dUMP to dTMP using the co-enzyme methylenetetrahydrofolate, and is perhaps the best studied of enzymes that catalyze carbon-carbon bond formation. Arg 126 is found in all TSs but forms only 1 of 13 hydrogen bonds to dUMP during catalysis, and just one of seven to the phosphate group alone. Despite this, when Arg 126 of TS from Escherichia coli was changed to glutamate (R126E), the resulting protein had kcat reduced 2000-fold and Km reduced 600-fold. The crystal structure of R126E was determined under two conditions--in the absence of bound ligand (2.4 A resolution), and with dUMP and the antifolate CB3717 (2.2 A resolution). The first crystals, which did not contain dUMP despite its presence in the crystallization drop, displayed Glu 126 in a position to sterically and electrostatically interfere with binding of the dUMP phosphate. The second crystals contained both dUMP and CB3717 in the active site, but Glu 126 formed three hydrogen bonds to nearby residues (two through water) and was in a position that partially overlapped with the normal phosphate binding site, resulting in a approximately 1 A shift in the phosphate group. Interestingly, the protein displayed the typical ligand-induced conformational change, and the covalent bond to Cys 146 was present in one of the protein's two active sites. | |||
Crystal structures of a marginally active thymidylate synthase mutant, Arg 126-->Glu.,Strop P, Changchien L, Maley F, Montfort WR Protein Sci. 1997 Dec;6(12):2504-11. PMID:9416600<ref>PMID:9416600</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1ajm" style="background-color:#fffaf0;"></div> | |||
==See Also== | ==See Also== | ||
*[[Thymidylate synthase|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: Montfort | [[Category: Montfort WR]] | ||
[[Category: Strop | [[Category: Strop P]] | ||
Latest revision as of 09:22, 30 October 2024
CRYSTAL STRUCTURE OF THYMIDYLATE SYNTHASE R126E MUTANTCRYSTAL STRUCTURE OF THYMIDYLATE SYNTHASE R126E 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) is a long-standing target for anticancer drugs and is of interest for its rich mechanistic features. The enzyme catalyzes the conversion of dUMP to dTMP using the co-enzyme methylenetetrahydrofolate, and is perhaps the best studied of enzymes that catalyze carbon-carbon bond formation. Arg 126 is found in all TSs but forms only 1 of 13 hydrogen bonds to dUMP during catalysis, and just one of seven to the phosphate group alone. Despite this, when Arg 126 of TS from Escherichia coli was changed to glutamate (R126E), the resulting protein had kcat reduced 2000-fold and Km reduced 600-fold. The crystal structure of R126E was determined under two conditions--in the absence of bound ligand (2.4 A resolution), and with dUMP and the antifolate CB3717 (2.2 A resolution). The first crystals, which did not contain dUMP despite its presence in the crystallization drop, displayed Glu 126 in a position to sterically and electrostatically interfere with binding of the dUMP phosphate. The second crystals contained both dUMP and CB3717 in the active site, but Glu 126 formed three hydrogen bonds to nearby residues (two through water) and was in a position that partially overlapped with the normal phosphate binding site, resulting in a approximately 1 A shift in the phosphate group. Interestingly, the protein displayed the typical ligand-induced conformational change, and the covalent bond to Cys 146 was present in one of the protein's two active sites. Crystal structures of a marginally active thymidylate synthase mutant, Arg 126-->Glu.,Strop P, Changchien L, Maley F, Montfort WR Protein Sci. 1997 Dec;6(12):2504-11. PMID:9416600[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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