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PDBsum entry 1e1f
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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 a monocotyledon (maize zmglu1) beta-Glucosidase and a model of its complex with p-Nitrophenyl beta-D-Thioglucoside.
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Authors
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M.Czjzek,
M.Cicek,
V.Zamboni,
W.P.Burmeister,
D.R.Bevan,
B.Henrissat,
A.Esen.
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Ref.
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Biochem J, 2001,
354,
37-46.
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PubMed id
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Abstract
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The maize beta-glucosidase isoenzymes ZMGlu1 and ZMGlu2 hydrolyse the abundant
natural substrate DIMBOAGlc
(2-O-beta-D-glucopyranosyl-4-hydroxy-7-methoxy-1,4-benzoxazin-3-one), whose
aglycone DIMBOA (2,4-hydroxy-7-methoxy-1,4-benzoxazin-3-one) is the major
defence chemical protecting seedlings and young plant parts against herbivores
and other pests. The two isoenzymes hydrolyse DIMBOAGlc with similar kinetics
but differ from each other and their sorghum homologues with respect to
specificity towards other substrates. To gain insights into the mechanism of
substrate (i.e. aglycone) specificity between the two maize isoenzymes and their
sorghum homologues, ZMGlu1 was produced in Escherichia coli, purified,
crystallized and its structure solved at 2.5 Angstrom resolution by X-ray
crystallography. In addition, the complex of ZMGlu1 with the non-hydrolysable
inhibitor p-nitrophenyl beta-D-thioglucoside was crystallized and, based on the
partial electron density, a model for the inhibitor molecule within the active
site is proposed. The inhibitor is located in a slot-like active site where its
aromatic aglycone is held by stacking interactions with Trp-378. Whereas some of
the atoms on the non-reducing end of the glucose moiety can be modelled on the
basis of the electron density, most of the inhibitor atoms are highly
disordered. This is attributed to the requirement of the enzyme to accommodate
two different species, namely the substrate in its ground state and in its
distorted conformation, for catalysis.
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Secondary reference #1
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Title
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Nucleotide sequence of a cdna corresponding to a second beta-Glucosidase gene in maize
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Authors
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H.Bandaranayake,
A.Esen.
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Ref.
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plant physiol, 1996,
110,
1048.
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