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PDBsum entry 1asp
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Oxidoreductase
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PDB id
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1asp
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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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X-Ray structures and mechanistic implications of three functional derivatives of ascorbate oxidase from zucchini. Reduced, Peroxide and azide forms.
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Authors
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A.Messerschmidt,
H.Luecke,
R.Huber.
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Ref.
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J Mol Biol, 1993,
230,
997.
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PubMed id
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Note In the PDB file this reference is
annotated as "TO BE PUBLISHED".
The citation details given above were identified by an automated
search of PubMed on title and author
names, giving a
percentage match of
91%.
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Abstract
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The X-ray structures of three functional derivatives of ascorbate oxidase (EC
1.10.3.3) from Zucchini have been determined and are compared to the "native"
oxidized form. The fully reduced form of ascorbate oxidase has been refined to a
crystallographic R-factor of 19.6% for all reflections between 8.0 A and 2.2 A
resolution. The geometry at the type-1 copper (CU1) is unchanged compared to the
oxidized form, but the oxygen ligand bridging the copper ions CU2 and CU3
(spectroscopic type-3 copper pair) is released and the copper ions move apart
yielding a trigonal planar co-ordination with their ligating histidine residues.
The co-ordination at the copper ion CU4 (spectroscopic type-2 copper) is not
affected. The copper-copper distances increase from an average 3.7 A in the
native form to 5.1 A for CU2-CU3, 4.4 A for CU2-CU4 and 4.1 A for CU3-CU4. The
peroxide derivative of ascorbate oxidase has been refined to a crystallographic
R-factor of 16.0% for all reflections between 8.0 A and 2.59 A resolution. The
geometry at the type-1 copper site is not changed compared to the oxidized form.
The oxygen ligand bridging copper atoms CU2 and CU3 is lost, too. The peroxide
binds terminally to the copper ion CU2 as hydroperoxide. Copper ion CU2 is
fourfold co-ordinated to the NE2 atoms of the three histidine residues and to
the oxygen atom of the terminally bound peroxide molecule in a distorted
tetrahedral geometry. Copper ion CU3 is threefold co-ordinated as in the reduced
form and co-ordination around copper atom CU4 is unaltered. The copper-copper
distances increase to 4.8 A for CU2-CU3 and 4.5 A for CU2-CU4. The distance
CU3-CU4 remains 3.7 A. Treatment with peroxide causes a partial depletion of
copper ion CU2. The refinement for the azide derivative of ascorbate oxidase
converged at a crystallographic R-factor of 17.8% for all reflections between
8.0 A and 2.32 A. There are no significant structural changes at the type-1
copper site. The oxygen ligand bridging copper ions CU2 and CU3 is again
released. Two azide molecules bind terminally to copper ion CU2. Copper ion CU2
is fivefold co-ordinated to the NE2 atoms of the three histidine residues and to
both terminally bound azide molecules in a trigonal-bipyramidal manner.
Copper-copper distances increase to 5.1 A for CU2-CU3 and 4.6 A for CU2-CU4. The
distance CU3-CU4 is decreased to 3.6 A.(ABSTRACT TRUNCATED AT 400 WORDS)
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Secondary reference #1
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Title
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Refined crystal structure of ascorbate oxidase at 1.9 a resolution.
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Authors
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A.Messerschmidt,
R.Ladenstein,
R.Huber,
M.Bolognesi,
L.Avigliano,
R.Petruzzelli,
A.Rossi,
A.Finazzi-Agró.
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Ref.
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J Mol Biol, 1992,
224,
179-205.
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PubMed id
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Secondary reference #2
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Title
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X-Ray crystal structure of the blue oxidase ascorbate oxidase from zucchini. Analysis of the polypeptide fold and a model of the copper sites and ligands.
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Authors
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A.Messerschmidt,
A.Rossi,
R.Ladenstein,
R.Huber,
M.Bolognesi,
G.Gatti,
A.Marchesini,
R.Petruzzelli,
A.Finazzi-Agró.
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Ref.
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J Mol Biol, 1989,
206,
513-529.
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PubMed id
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