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PDBsum entry 5ej6
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References listed in PDB file
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Key reference
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Title
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A thiamine-Dependent enzyme utilizes an active tetrahedral intermediate in vitamin k biosynthesis.
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Authors
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H.Song,
C.Dong,
M.Qin,
Y.Chen,
Y.Sun,
J.Liu,
W.Chan,
Z.Guo.
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Ref.
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J Am Chem Soc, 2016,
138,
7244-7247.
[DOI no: ]
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PubMed id
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Abstract
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Enamine is a well-known reactive intermediate mediating essential
thiamine-dependent catalysis in central metabolic pathways. However, this
intermediate is not found in the thiamine-dependent catalysis of the vitamin K
biosynthetic enzyme MenD. Instead, an active tetrahedral post-decarboxylation
intermediate is stably formed in the enzyme and was structurally determined at
1.34 Å resolution in crystal. This intermediate takes a unique conformation
that allows only one proton between its tetrahedral reaction center and the
exo-ring nitrogen atom of the aminopyrimidine moiety in the cofactor with a
short distance of 3.0 Å. 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.
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