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PDBsum entry 1fbx
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Zinc plays a key role in human and bacterial gtp cyclohydrolase i.
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Authors
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G.Auerbach,
A.Herrmann,
A.Bracher,
G.Bader,
M.Gutlich,
M.Fischer,
M.Neukamm,
M.Garrido-Franco,
J.Richardson,
H.Nar,
R.Huber,
A.Bacher.
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Ref.
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Proc Natl Acad Sci U S A, 2000,
97,
13567-13572.
[DOI no: ]
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PubMed id
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Abstract
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The crystal structure of recombinant human GTP cyclohydrolase I was solved by
Patterson search methods by using the coordinates of the Escherichia coli enzyme
as a model. The human as well as bacterial enzyme were shown to contain an
essential zinc ion coordinated to a His side chain and two thiol groups in each
active site of the homodecameric enzymes that had escaped detection during
earlier studies of the E. coli enzyme. The zinc ion is proposed to generate a
hydroxyl nucleophile for attack of imidazole ring carbon atom eight of the
substrate, GTP. It may also be involved in the hydrolytic release of formate
from the intermediate, 2-amino-5-formylamino-6-ribosylamino-4(3H)-pyrimidinone
5'-triphosphate, and in the consecutive Amadori rearrangement of the ribosyl
moiety.
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Figure 1.
Fig. 1. Stereo view of the active site of (a) hGTP-CH-I
and (b) eGTP-CH-I harboring zinc. The averaged 2F[o]  F[c]
electron density maps are shown in blue.
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Figure 4.
Fig. 4. Hypothetical reaction mechanism for GTP-CH-I.
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