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PDBsum entry 5d4t
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Unknown function
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PDB id
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5d4t
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References listed in PDB file
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Key reference
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Title
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Identification of hcgc as a sam-Dependent pyridinol methyltransferase in [fe]-Hydrogenase cofactor biosynthesis.
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Authors
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T.Fujishiro,
L.Bai,
T.Xu,
X.Xie,
M.Schick,
J.Kahnt,
M.Rother,
X.Hu,
U.Ermler,
S.Shima.
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Ref.
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Angew Chem Int Ed Engl, 2016,
55,
9648-9651.
[DOI no: ]
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PubMed id
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Abstract
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Previous retrosynthetic and isotope-labeling studies have indicated that
biosynthesis of the iron guanylylpyridinol (FeGP) cofactor of [Fe]-hydrogenase
requires a methyltransferase. This hypothetical enzyme covalently attaches the
methyl group at the 3-position of the pyridinol ring. We describe the
identification of HcgC, a gene product of the hcgA-G cluster responsible for
FeGP cofactor biosynthesis. It acts as an S-adenosylmethionine (SAM)-dependent
methyltransferase, based on the crystal structures of HcgC and the HcgC/SAM and
HcgC/S-adenosylhomocysteine (SAH) complexes. The pyridinol substrate,
6-carboxymethyl-5-methyl-4-hydroxy-2-pyridinol, was predicted based on
properties of the conserved binding pocket and substrate docking simulations.
For verification, the assumed substrate was synthesized and used in a kinetic
assay. Mass spectrometry and NMR analysis revealed
6-carboxymethyl-3,5-dimethyl-4-hydroxy-2-pyridinol as the reaction product,
which confirmed the function of HcgC.
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