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| | ==ThDP-Mn2+ complex of R413K variant of EcMenD soaked with 2-ketoglutarate for 5 min== | | ==ThDP-Mn2+ complex of R413K variant of EcMenD soaked with 2-ketoglutarate for 5 min== |
| - | <StructureSection load='5z2p' size='340' side='right' caption='[[5z2p]], [[Resolution|resolution]] 2.30Å' scene=''> | + | <StructureSection load='5z2p' size='340' side='right'caption='[[5z2p]], [[Resolution|resolution]] 2.30Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[5z2p]] is a 8 chain structure with sequence from [http://en.wikipedia.org/wiki/Ecoli Ecoli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5Z2P OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5Z2P FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[5z2p]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5Z2P OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5Z2P FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=FMT:FORMIC+ACID'>FMT</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=MN:MANGANESE+(II)+ION'>MN</scene>, <scene name='pdbligand=TD6:(4S)-4-{3-[(4-AMINO-2-METHYLPYRIMIDIN-5-YL)METHYL]-5-(2-{[(S)-HYDROXY(PHOSPHONOOXY)PHOSPHORYL]OXY}ETHYL)-4-METHYL-1,3LAMBDA~5~-THIAZOL-2-YL}-4-HYDROXYBUTANOIC+ACID'>TD6</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.3Å</td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">menD, b2264, JW5374 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=83333 ECOLI])</td></tr>
| + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FMT:FORMIC+ACID'>FMT</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=MN:MANGANESE+(II)+ION'>MN</scene>, <scene name='pdbligand=TD6:(4S)-4-{3-[(4-AMINO-2-METHYLPYRIMIDIN-5-YL)METHYL]-5-(2-{[(S)-HYDROXY(PHOSPHONOOXY)PHOSPHORYL]OXY}ETHYL)-4-METHYL-1,3LAMBDA~5~-THIAZOL-2-YL}-4-HYDROXYBUTANOIC+ACID'>TD6</scene></td></tr> |
| - | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylic-acid_synthase 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylic-acid synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.2.1.9 2.2.1.9] </span></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=5z2p FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5z2p OCA], [https://pdbe.org/5z2p PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5z2p RCSB], [https://www.ebi.ac.uk/pdbsum/5z2p PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5z2p ProSAT]</span></td></tr> |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5z2p FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5z2p OCA], [http://pdbe.org/5z2p PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5z2p RCSB], [http://www.ebi.ac.uk/pdbsum/5z2p PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5z2p ProSAT]</span></td></tr> | + | |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/MEND_ECOLI MEND_ECOLI]] Catalyzes the thiamine diphosphate-dependent decarboxylation of 2-oxoglutarate and the subsequent addition of the resulting succinic semialdehyde-thiamine pyrophosphate anion to isochorismate to yield 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylate (SEPHCHC).<ref>PMID:1459959</ref> <ref>PMID:17760421</ref> | + | [https://www.uniprot.org/uniprot/MEND_ECOLI MEND_ECOLI] Catalyzes the thiamine diphosphate-dependent decarboxylation of 2-oxoglutarate and the subsequent addition of the resulting succinic semialdehyde-thiamine pyrophosphate anion to isochorismate to yield 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylate (SEPHCHC).<ref>PMID:1459959</ref> <ref>PMID:17760421</ref> |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylic-acid synthase]] | + | [[Category: Escherichia coli K-12]] |
| - | [[Category: Ecoli]] | + | [[Category: Large Structures]] |
| - | [[Category: Guo, Z H]] | + | [[Category: Guo ZH]] |
| - | [[Category: Qin, M M]] | + | [[Category: Qin MM]] |
| - | [[Category: Complex]]
| + | |
| - | [[Category: Transferase]]
| + | |
| Structural highlights
Function
MEND_ECOLI Catalyzes the thiamine diphosphate-dependent decarboxylation of 2-oxoglutarate and the subsequent addition of the resulting succinic semialdehyde-thiamine pyrophosphate anion to isochorismate to yield 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylate (SEPHCHC).[1] [2]
Publication Abstract from PubMed
The bacterial enzyme MenD, or 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylate (SEPHCHC) synthase, catalyzes an essential Stetter reaction in menaquinone (vitamin K2) biosynthesis via thiamine diphosphate (ThDP)-bound tetrahedral post-decarboxylation intermediates. The detailed mechanism of this intermediate chemistry, however, is still poorly understood, but of significant interest given that menaquinone is an essential electron transporter in many pathogenic bacteria. Here, we used site-directed mutagenesis, enzyme kinetic assays, and protein crystallography to reveal an active-inactive intermediate equilibrium in MenD catalysis and its modulation by two conserved active-site arginine residues. We observed that these conserved residues play a key role in shifting the equilibrium to the active intermediate by orienting the C2-succinyl group of the intermediates through strong ionic hydrogen bonding. We found that when this interaction is moderately weakened by amino acid substitutions, the resulting proteins are catalytically competent, with the C2-succinyl group taking either the active or the inactive orientation in the post-decarboxylation intermediate. When this hydrogen-bonding interaction was strongly weakened, the succinyl group was re-oriented by 180 degrees relative to the native intermediate, resulting in reversal of the stereochemistry at the reaction center that disabled catalysis. Interestingly, this inactive intermediate was formed with a distinct kinetic behavior, likely as a result of a nonnative mode of enzyme-substrate interaction. The mechanistic insights gained from these findings improve our understanding of the new ThDP-dependent catalysis. More importantly, the nonnative binding site of the inactive MenD intermediate uncovered here provides a new target for development of antibiotics.
Two active site arginines are critical determinants of substrate binding and catalysis in MenD, a thiamine-dependent enzyme in menaquinone biosynthesis.,Qin M, Song H, Dai X, Chen Y, Guo Z Biochem J. 2018 Oct 19. pii: BCJ20180548. doi: 10.1042/BCJ20180548. PMID:30341164[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Palaniappan C, Sharma V, Hudspeth ME, Meganathan R. Menaquinone (vitamin K2) biosynthesis: evidence that the Escherichia coli menD gene encodes both 2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylic acid synthase and alpha-ketoglutarate decarboxylase activities. J Bacteriol. 1992 Dec;174(24):8111-8. PMID:1459959
- ↑ Jiang M, Cao Y, Guo ZF, Chen M, Chen X, Guo Z. Menaquinone biosynthesis in Escherichia coli: identification of 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylate as a novel intermediate and re-evaluation of MenD activity. Biochemistry. 2007 Sep 25;46(38):10979-89. Epub 2007 Aug 31. PMID:17760421 doi:http://dx.doi.org/10.1021/bi700810x
- ↑ Qin M, Song H, Dai X, Chen Y, Guo Z. Two active site arginines are critical determinants of substrate binding and catalysis in MenD, a thiamine-dependent enzyme in menaquinone biosynthesis. Biochem J. 2018 Oct 19. pii: BCJ20180548. doi: 10.1042/BCJ20180548. PMID:30341164 doi:http://dx.doi.org/10.1042/BCJ20180548
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