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PDBsum entry 1a7l
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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 dominant b-Cell epitope from the pres2 region of hepatitis b virus in the form of an inserted peptide segment in maltodextrin-Binding protein.
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Authors
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F.A.Saul,
B.Vulliez-Le normand,
F.Lema,
G.A.Bentley.
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Ref.
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J Mol Biol, 1998,
280,
185-192.
[DOI no: ]
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PubMed id
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Abstract
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We report here the crystal structure of MalE-B363, a recombinant construction of
maltodextrin-binding protein bearing a dominant B-cell epitope sequence from the
preS2 region of the hepatitis B surface antigen. The inserted peptide sequence,
which replaces the seven carboxy-terminal residues of maltodextrin-binding
protein, carries the 14 amino acid residue epitope contained between residues
132 and 145 from the preS2 region. The epitope sequence is flanked on either
side by additional residues that result from the genetically engineered
insertion, bringing the total length of the foreign peptide to 26 amino acid
residues. The hybrid protein has been previously shown to be recognised by
monoclonal antibodies elicited by the native viral antigen. Three independent
molecules of MalE-B363 are present in the asymmetric unit of the crystal. All 14
epitope residues could be traced for one molecule, ten epitope residues had
significant electron density for the second, but no density was visible for the
epitope of the third. The conformation of the amino-terminal segment of the
epitope from Gln132(e) to Gly138(e) is similar in the two molecules of MalE-B363
for which the foreign peptide could be traced. Moreover, the conformation of a
smaller segment, comprising residues Asp133(e) to Arg137(e), is similar to that
present in the previously determined crystal structure of MalE-B133, another
insertion/deletion mutant of maltodextrin-binding protein bearing the preS2
epitope. The presence of a common structural motif for the same sequence in
disparate molecular environments suggests that this conformation might be
present also in the native viral antigen. This could provide a structural basis
to explain the cross-reactivity of anti-preS2 monoclonal antibodies with these
hybrid proteins.
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Figure 1.
Figure 1. Schematic view of MalE-B363 in stereo; (a)
molecule 1 and (b) molecule 2. The genetically inserted peptide
at the carboxy terminus of the hybrid is shown in red and the
bound molecule of maltose is shown in blue. Illustrations were
produced by MOLSCRIPT [Kraulis 1991].
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Figure 2.
Figure 2. Stereo view of the electron density corresponding
to the genetically inserted peptide in MalE-B363 (a) from
residues 364(i) to 383(i) in molecule 1 and (b) from residues
364(i) to 141(e) in molecule 2. Contours are drawn at the 1
r.m.s. level of a (2F[o]−F[c]) electron density map. No
significant electron density was observed for the epitope
insertion in molecule 3.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(1998,
280,
185-192)
copyright 1998.
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Secondary reference #1
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Title
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Maltodextrin-Binding protein hybrids carrying epitopes from the pres2 region of hepatitis b virus: expression, Antibody-Binding and preliminary crystallographic studies.
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Authors
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B.Vulliez-Le normand,
F.A.Saul,
P.Martineau,
F.Lema,
M.Hofnung,
G.A.Bentley.
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Ref.
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Protein Eng, 1997,
10,
175-180.
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PubMed id
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