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PDBsum entry 2o2l
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Contents |
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98 a.a.
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(+ 3 more)
103 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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Blood group antigen recognition by escherichia coli heat-Labile enterotoxin.
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Authors
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A.Holmner,
G.Askarieh,
M.Okvist,
U.Krengel.
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Ref.
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J Mol Biol, 2007,
371,
754-764.
[DOI no: ]
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PubMed id
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Abstract
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In a number of bacterial infections, such as Helicobacter pylori, Campylobacter
jejuni and Vibrio cholerae infections, a correlation between the severity of
disease and blood group phenotype of infected individuals has been observed. In
the present investigation, we have studied the molecular basis of this effect
for enterotoxigenic Escherichia coli (ETEC) infections. ETEC are non-invasive
bacteria, which act through second messenger pathways to cause diarrhea. It has
been suggested that the major virulence factor of ETEC from human isolates, i.e.
the human heat-labile enterotoxin (hLT), recognizes certain blood group
epitopes, although the molecular basis of blood group antigen recognition is
unknown. The 2.5 A crystal structure of the receptor-binding B-subunit of hLT in
complex with the blood group A antigen analog
GalNAcalpha3(Fucalpha2)Galbeta4(Fucalpha3)Glcbeta provides evidence of a
previously unknown binding site in the native toxin. The structure reveals the
molecular interactions underlying blood group antigen recognition and suggests
how this protein can discriminate between different blood group epitopes. These
results support the previously debated role of hLT in the blood group dependence
of ETEC infections. Similar observations regarding the closely related cholera
toxin in V. cholera infections are also discussed.
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Figure 1.
Figure 1. (a) Surface representation of the hLT B-pentamer.
The blood group A antigen analog
GalNAcα3(Fucα2)Galβ4(Fucα3)Glcβ is shown in red stick
representation. A model of the GM1 pentasaccharide (black) is
depicted for comparison. (b) Well-defined electron density
(2F[o]−F[c] map, at 1σ) of the pentasaccharide, at the
interface of two B-subunits (in green and blue, respectively)
The Figure was generated with PyMOL: DeLano, W.L.
[http://www.pymol.org].
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Figure 2.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2007,
371,
754-764)
copyright 2007.
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