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PDBsum entry 1gpe
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Oxidoreductase(flavoprotein)
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PDB id
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1gpe
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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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1.8 and 1.9 a resolution structures of the penicillium amagasakiense and aspergillus niger glucose oxidases as a basis for modelling substrate complexes.
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Authors
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G.Wohlfahrt,
S.Witt,
J.Hendle,
D.Schomburg,
H.M.Kalisz,
H.J.Hecht.
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Ref.
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Acta Crystallogr D Biol Crystallogr, 1999,
55,
969-977.
[DOI no: ]
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PubMed id
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Abstract
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Glucose oxidase is a flavin-dependent enzyme which catalyses the oxidation of
beta-D-glucose by molecular oxygen to delta-gluconolactone and hydrogen
peroxide. The structure of the enzyme from Aspergillus niger, previously refined
at 2.3 A resolution, has been refined at 1.9 A resolution to an R value of
19.0%, and the structure of the enzyme from Penicillium amagasakiense, which has
65% sequence identity, has been determined by molecular replacement and refined
at 1.8 A resolution to an R value of 16.4%. The structures of the partially
deglycosylated enzymes have an r.m.s. deviation of 0.7 A for main-chain atoms
and show four N-glycosylation sites, with an extended carbohydrate moiety at
Asn89. Substrate complexes of the enzyme from A. niger were modelled by
force-field methods. The resulting model is consistent with results from
site-directed mutagenesis experiments and shows the beta-D-glucose molecule in
the active site of glucose oxidase, stabilized by 12 hydrogen bonds and by
hydrophobic contacts to three neighbouring aromatic residues and to flavin
adenine dinucleotide. Other hexoses, such as alpha-D-glucose, mannose and
galactose, which are poor substrates for the enzyme, and 2-deoxy-D-glucose, form
either fewer bonds or unfavourable contacts with neighbouring amino acids.
Simulation of the complex between the reduced enzyme and the product,
delta-gluconolactone, has provided an explanation for the lack of product
inhibition by the lactone.
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Figure 1.
Figure 1 Schematic representation of the glucose oxidase
reaction showing the inhibitor D-glucal in the insert. For  -D-glucose
and the flavin group the atom-numbering scheme used in the text
is indicated. Gluconolactone, gluconic acid and the inhibitor
D-glucal are numbered accordingly.
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Figure 6.
Figure 6 Schematic representation of the hydrogen bonds and
hydrophobic interactions of the modelled substrate -D-glucose
with active-site residues in glucose oxidase from A. niger
(LIGPLOT; Wallace et al., 1995[Wallace, A. C., Laskowski, R. A.
& Thornton, J. M. (1995). Protein Eng. 8, 127-134.]).
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The above figures are
reprinted
by permission from the IUCr:
Acta Crystallogr D Biol Crystallogr
(1999,
55,
969-977)
copyright 1999.
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