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PDBsum entry 3efx
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96 a.a.
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96 a.a.
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95 a.a.
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100 a.a.
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93 a.a.
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102 a.a.
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References listed in PDB file
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Key reference
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Title
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Novel binding site identified in a hybrid between cholera toxin and heat-Labile enterotoxin: 1.9 a crystal structure reveals the details.
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Authors
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A.Holmner,
M.Lebens,
S.Teneberg,
J.Angström,
M.Okvist,
U.Krengel.
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Ref.
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Structure, 2004,
12,
1655-1667.
[DOI no: ]
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PubMed id
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Abstract
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A hybrid between the B subunits of cholera toxin and Escherichia coli
heat-labile enterotoxin has been described, which exhibits a novel binding
specificity to blood group A and B type 2 determinants. In the present
investigation, we have determined the crystal structure of this protein hybrid,
termed LCTBK, in complex with the blood group A pentasaccharide
GalNAcalpha3(Fucalpha2)Galbeta4(Fucalpha3)GlcNAcbeta, confirming not only the
novel binding specificity but also a distinct new oligosaccharide binding site.
Binding studies revealed that the new specificity can be ascribed to a single
mutation (S4N) introduced into the sequence of Escherichia coli heat-labile
enterotoxin. At a resolution of 1.9 A, the new binding site is resolved in
excellent detail. Main features include a complex network of water molecules,
which is well preserved by the parent toxins, and an unexpectedly modest
contribution to binding by the critical residue Asn4, which interacts with the
ligand only via a single water molecule.
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Figure 4.
Figure 4. View of the Novel Binding Site in a Shallow
Groove at the Interface of Two B Subunits of LCTBK(A) Overview
picture. The blood group A pentasaccharide is shown in stick
representation; the GM1 pentasaccharide is indicated by white
spheres. (Inset: positions of the novel binding site and the GM1
binding site within the B-pentamer, marked with red and white
circles, respectively). Please note that the carbohydrate ligand
is only displayed for one of the five equivalent binding sites
within the B-pentamer.(B) Close-up view of the blood group A
binding site, featuring the two separate water networks (figure
generated with Swiss-PdbViewer and POV-Ray).
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The above figure is
reprinted
by permission from Cell Press:
Structure
(2004,
12,
1655-1667)
copyright 2004.
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Secondary reference #1
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Title
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Novel binding site identified in a hybrid between cholera toxin and heat-Labile enterotoxin: 1.9 a crystal structure reveals the details
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Authors
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A.Holmner,
M.Lebens,
S.Teneberg,
J.Angstrom,
M.Okvist,
U.Krengel.
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Ref.
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structure, 2007,
15,
253.
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