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PDBsum entry 1f2d
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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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Crystal structure of 1-Aminocyclopropane-1-Carboxylate deaminase from hansenula saturnus.
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Authors
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M.Yao,
T.Ose,
H.Sugimoto,
A.Horiuchi,
A.Nakagawa,
S.Wakatsuki,
D.Yokoi,
T.Murakami,
M.Honma,
I.Tanaka.
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Ref.
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J Biol Chem, 2000,
275,
34557-34565.
[DOI no: ]
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PubMed id
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Abstract
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The pyridoxal 5'-phosphate (PLP)-dependent enzyme
1-aminocyclopropane-1-carboxylate deaminase (ACCD) catalyzes a reaction that
involves a ring opening of cyclopropanoid amino acid, yielding
alpha-ketobutyrate and ammonia. Unlike other PLP-dependent enzymes, this enzyme
has no alpha-hydrogen atom in the substrate. Thus, a unique mechanism for the
bond cleavage is expected. The crystal structure of ACCD from Hansenula saturnus
has been determined at 2.0 A resolution by the multiple wavelength anomalous
diffraction method using mercury atoms as anomalous scatterers. The model was
built on the electron density map, which was obtained by the density averaging
of multiple crystal forms. The final model was refined to an R-factor of 22.5%
and an R(free)-factor of 26.8%. The ACCD folds into two domains, each of which
has an open twisted alpha/beta structure similar to the beta-subunit of
tryptophan synthase. However, in ACCD, unlike in other members of the beta
family of PLP-dependent enzymes, PLP is buried deep in the molecule. The
structure provides the first view of the catalytic center of the cyclopropane
ring opening.
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Figure 8.
Fig. 8. Hydrogen bonding networks around the active site.
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Figure 9.
Fig. 9. A detailed view of the PLP-binding site and
proposed substrate complex. ACC is modeled on the electron
density for the bound sulfoxide ion. Thin bonds are hypothetical
drawings of PLP and the bound substrate (see "Reaction
Mechanism").
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2000,
275,
34557-34565)
copyright 2000.
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