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PDBsum entry 2v3e
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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 structures of complexes of n-Butyl- And n-Nonyl-Deoxynojirimycin bound to acid-Beta -Glucosidase: insights into the mechanism of chemical chaperone action in gaucher disease.
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Authors
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B.Brumshtein,
H.M.Greenblatt,
T.D.Butters,
Y.Shaaltiel,
D.Aviezer,
I.Silman,
A.H.Futerman,
J.L.Sussman.
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Ref.
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J Biol Chem, 2007,
282,
29052.
[DOI no: ]
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PubMed id
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Abstract
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Gaucher disease is caused by mutations in the gene encoding
acid-beta-glucosidase (GlcCerase), resulting in glucosylceramide (GlcCer)
accumulation. The only currently-available orally-administered treatment for
Gaucher disease is N-butyl-deoxynojirimycin (Zavescatrade mark, NB-DNJ), which
partially inhibits GlcCer synthesis, thus reducing levels of GlcCer
accumulation. NB-DNJ also acts as a chemical chaperone for GlcCerase, although
at a different concentration to that required to completely inhibit GlcCer
synthesis. We now report the crystal structures, at 2A resolution, of complexes
of NB-DNJ and N-nonyl-deoxynojirimycin (NN-DNJ) with recombinant human
GlcCerase, expressed in cultured plant cells. Both inhibitors bind at the active
site of GlcCerase, with the imino-sugar moiety making hydrogen bonds to side
chains of active-site residues. The alkyl chains of NB-DNJ and NN-DNJ are
oriented towards the entrance of the active site where they undergo hydrophobic
interactions. Based on these structures, we make a number of predictions
concerning (i) involvement of loops adjacent to the active site in the catalytic
process, (ii) the nature of nucleophilic attack by Glu340, and (iii) the role of
a conserved water molecule located in a solvent cavity adjacent to the active
site. Together, these results have significance for understanding the mechanism
of action of GlcCerase, and the mode of GlcCerase chaperoning by imino sugars.
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Figure 2.
FIGURE 2. Comparison of binding of non-covalent inhibitors
to GlcCerase. A, NN-DNJ/pGlcCerase. B, NB-DNJ/pGlcCerase. C,
IFG/DG-Cerezyme. Green lines represent hydrogen bonds and red
lines hydrophobic interactions. L1, loop 1 (residues 341-350);
L2, loop 2 (residues 393-396); L3, loop 3 (residues 312-319).
314(B) in panel A corresponds to the side chain of a
symmetrically related molecule.
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Figure 4.
FIGURE 4. Conformations of the loops at the entrance to the
active site. The loops in GlcCerase occur in a number of
conformations, but only two are shown for clarity, in yellow and
green; these conformations give the most pronounced changes in
the entrance to the active site. Tyr-313, which may play a role
in the catalytic mechanism, is indicated. The catalytic residues
are shown as red sticks.
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2007,
282,
29052-0)
copyright 2007.
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