Structural highlights
5ej4 is a 8 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
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| Ligands: | , , , |
| Related: | 5ej5, 5ej6, 5ej7, 5ej8, 5ej9, 5eja, 5ejm |
| Activity: | 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylic-acid synthase, with EC number 2.2.1.9 |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
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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
Enamine is a well-known reactive intermediate mediating essential thiamine-dependent catalysis in central metabolic pathways. How-ever, this intermediate is not found in the thiamine-dependent catal-ysis of the vitamin K biosynthetic enzyme MenD. Instead, an active tetrahedral post-decarboxylation intermediate is stably formed in the enzyme and structurally determined at 1.34 A resolution in crystal. This intermediate takes a unique conformation that allows only one proton between its tetrahedral reaction center and the exo-ring ni-trogen atom of the aminopyrimidine moiety in the cofactor with a short distance of 3.0 A. It is readily convertible to the final product of the enzymic reaction with a solvent-exchangeable proton at its reaction center. These results show that the thiamine-dependent enzyme utilizes a tetrahedral intermediate in a mechanism distinct from the enamine catalytic chemistry.
A thiamine-dependent enzyme utilizes an active tetrahedral intermediate in vitamin K biosynthesis.,Song H, Dong C, Qin M, Chen Y, Sun Y, Liu J, Chan W, Guo Z J Am Chem Soc. 2016 May 23. PMID:27213829[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
- ↑ Song H, Dong C, Qin M, Chen Y, Sun Y, Liu J, Chan W, Guo Z. A thiamine-dependent enzyme utilizes an active tetrahedral intermediate in vitamin K biosynthesis. J Am Chem Soc. 2016 May 23. PMID:27213829 doi:http://dx.doi.org/10.1021/jacs.6b03437
