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PDBsum entry 1k7b
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Membrane protein
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PDB id
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1k7b
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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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The solution structure of the viral binding domain of tva, The cellular receptor for subgroup a avian leukosis and sarcoma virus.
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Authors
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M.Tonelli,
R.J.Peters,
T.L.James,
D.A.Agard.
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Ref.
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FEBS Lett, 2001,
509,
161-168.
[DOI no: ]
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PubMed id
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Abstract
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The cellular receptor for subgroup A avian leukosis and sarcoma virus (ALSV-A)
is Tva, which contains a motif related to repeats in the low density lipoprotein
receptor (LDLR) ligand binding repeat (LBr) and which is necessary for viral
entry. As observed with LBr repeats of LDLR, the 47 residue LBr domain of Tva
(sTva47) requires calcium during oxidative folding to form the correct disulfide
bonds, and calcium enhances the structure of correctly oxidized sTva47, as well
as its ability to bind the viral envelope protein (Env). However, solution
nuclear magnetic resonance studies indicate that, even in the presence of excess
calcium, sTva47 exists in an ensemble of conformations. Nonetheless, as reported
here, the structure of the predominant sTva47 solution conformer closely
resembles that of other LBr repeats, with identical S-S binding topology and
octahedral calcium coordination. The location of W48 and other critical residues
on the surface suggests a region of the molecule necessary for Env binding and
to mediate post-binding events important for ALSV-A cell entry.
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Figure 4.
Fig. 4. A: Comparison of the backbone atom coordinates of
sTva47 (light blue) and LR5 (red), the fifth repeat of LDLR that
was chosen as representative of the LBr domain fold (residues
24–46 of sTva47 were superimposed to residues 17–39 of LR5).
B: Comparison of the calcium binding sites of sTva47 and LR5.
The H-bond formed between H38 and D40 of Tva is also shown in
green. The coordinates of LR5 were obtained from the PDB (1ajj).
Structural comparisons were performed using the program MOLMOL
[40].
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Figure 5.
Fig. 5. A–C: Molecular surface of the sTva47 structure
colored by electrostatic potential. In B and C, the modules are
rotated  vert,
similar 90° around the vertical axis. This figure was prepared
with the program MOLMOL [40].
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The above figures are
reprinted
by permission from the Federation of European Biochemical Societies:
FEBS Lett
(2001,
509,
161-168)
copyright 2001.
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