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PDBsum entry 1uos
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Sugar binding protein
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PDB id
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1uos
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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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Structure of the snake-Venom toxin convulxin.
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Authors
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T.Batuwangala,
M.Leduc,
J.M.Gibbins,
C.Bon,
E.Y.Jones.
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Ref.
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Acta Crystallogr D Biol Crystallogr, 2004,
60,
46-53.
[DOI no: ]
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PubMed id
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Abstract
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Snake venoms contain a number of proteins that interact with components of the
haemostatic system that promote or inhibit events leading to blood-clot
formation. The snake-venom protein convulxin (Cvx) binds glycoprotein (GP) VI,
the platelet receptor for collagen, and triggers signal transduction. Here, the
2.7 A resolution crystal structure of Cvx is presented. In common with other
members of this snake-venom protein family, Cvx is an alphabeta-heterodimer and
conforms to the C-type lectin-fold topology. Comparison with other family
members allows a set of Cvx residues that form a concave surface to be
putatively implicated in GPVI binding. Unlike other family members, with the
exception of flavocetin-A (FL-A), Cvx forms an (alphabeta)(4) tetramer. This
oligomeric structure is consistent with Cvx clustering GPVI molecules on the
surface of platelets and as a result promoting signal transduction activity. The
Cvx structure and the location of the putative binding sites suggest a model for
this multimeric signalling assembly.
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Figure 3.
Figure 3 Analysis of the concave surface of Cvx. (a) Surface
representation of the Cvx tetramer. (b) Orientation of the
concave surface relative to the rest of the molecule.  -
and  -subunits
are coloured blue and red, respectively. The van der Waals
surface of the -heterodimer
is depicted in transparent grey and the concave surface with a
transparent brown tint. Relative orientations of views are
given. (c) Close-up view of the concave surface of the -heterodimer.
Residues contributing to charged patches are indicated. (d)
Schematic representation of the Cvx tetramer interaction with
protein ligand at the cell surface. The Cvx tetramer is depicted
as in Fig. 1-(a) with a 120° rotation about the horizontal.
Ligand molecules interacting at each concave surface are
depicted as transparent gold spheres. The cell surface is
depicted in grey.
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Figure 4.
Figure 4 Homology modelling and analysis of GPVI. (a) Sequence
alignment between GPVI and Lir-1. (b) C^ trace
of the GPVI model in coil representation; side chains of
residues contributing to charged patches are drawn in
ball-and-stick representation. (c) Surface representation of
GPVI model showing distribution of electrostatic potential
coloured in blue (positive) and red (negative) viewed in three
orientations. The starting orientation is as in (b).
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The above figures are
reprinted
by permission from the IUCr:
Acta Crystallogr D Biol Crystallogr
(2004,
60,
46-53)
copyright 2004.
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