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PDBsum entry 2adf
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Blood clotting/immune system
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PDB id
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2adf
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Contents |
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189 a.a.
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218 a.a.
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209 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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Paratope determination of the antithrombotic antibody 82d6a3 based on the crystal structure of its complex with the von willebrand factor a3-Domain.
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Authors
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S.Staelens,
M.A.Hadders,
S.Vauterin,
C.Platteau,
M.De maeyer,
K.Vanhoorelbeke,
E.G.Huizinga,
H.Deckmyn.
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Ref.
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J Biol Chem, 2006,
281,
2225-2231.
[DOI no: ]
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PubMed id
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Abstract
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The antithrombotic monoclonal antibody 82D6A3 is directed against amino acids
Arg-963, Pro-981, Asp-1009, Arg-1016, Ser-1020, Met-1022, and His-1023 of the
von Willebrand factor A3-domain (Vanhoorelbeke, K., Depraetere, H., Romijn, R.
A., Huizinga, E., De Maeyer, M., and Deckmyn, H. (2003) J. Biol. Chem. 278,
37815-37821). By this, it potently inhibits the interaction of von Willebrand
factor to collagens, which is a prerequisite for blood platelet adhesion to the
injured vessel wall at sites of high shear. To fully understand the mode of
action of 82D6A3 at the molecular level, we resolved its crystal structure in
complex with the A3-domain and fine mapped its paratope by construction and
characterization of 13 mutants. The paratope predominantly consists of two short
sequences in the heavy chain CDR1 (Asn-31 and Tyr-32) and CDR3 (Asp-99, Pro-101,
Tyr-102 and Tyr-103), forming one patch on the surface of the antibody. Trp-50
of the heavy and His-49 of the light chain, both situated adjacent to the patch,
play ancillary roles in antigen binding. The crystal structure furthermore
confirms the epitope location, which largely overlaps with the collagen binding
site deduced from mutagenesis of the A3-domain (Romijn, R. A., Westein, E.,
Bouma, B., Schiphorst, M. E., Sixma, J. J., Lenting, P. J., and Huizinga, E. G.
(2003) J. Biol. Chem. 278, 15035-15039). We herewith further consolidate the
location of the collagen binding site and reveal that the potent action of the
antibody is due to direct competition for the same interaction site. This
information allows the design of a paratope-mimicking peptide with
antithrombotic properties.
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Figure 2.
FIGURE 2. Interactions between 82D6A3 and the VWF
A3-domain. Close-up views of CDRs and interacting regions of the
A3-domain. Residues that have intermolecular contacts closer
than 4 Å are depicted in stick representation. Hydrogen
bonds and salt bridges are shown as dashed lines. Coloring of
ribbons and loops is identical to Fig. 1A.
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Figure 5.
FIGURE 5. The paratope of 82D6A3. A, ribbon diagram of the
variable domains of 82D6A3 with amino acids of the paratope
shown in stick representation and colored according to the
extent of residual VWF binding observed if mutated to alanine:
0–40%, red; 40–80%, yellow; 80–100%, green. B, surface
representation of the variable domains of 82D6A3 with surfaces
corresponding to residues in the paratope color coded as in
panel A.
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2006,
281,
2225-2231)
copyright 2006.
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