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PDBsum entry 1sb2
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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 rhodocetin reveals noncovalently bound heterodimer interface.
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Authors
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P.Paaventhan,
C.Kong,
J.S.Joseph,
M.C.Chung,
P.R.Kolatkar.
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Ref.
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Protein Sci, 2005,
14,
169-175.
[DOI no: ]
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PubMed id
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Abstract
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Rhodocetin is a unique heterodimer consisting of alpha- and beta-subunits of 133
and 129 residues, respectively. The molecule, purified from the crude venom of
the Malayan pit viper, Calloselasma rhodostoma, functions as an inhibitor of
collagen-induced aggregation. Rhodocetin has been shown to have activity only
when present as a dimer. The dimer is formed without an intersubunit disulfide
bridge, unlike all the other Ca(2+)-dependent lectin-like proteins. We report
here the 1.9 A resolution structure of rhodocetin, which reveals the
compensatory interactions that occur in the absence of the disulfide bridge to
preserve activity.
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Figure 4.
Figure 4. Superposition of subunits A in IX/X-bp (red),
IX-bp (green), and botrocetin (yellow) with rhodocetin  -subunit (blue)
shows that the loop in rhodocetin spanning 27 residues is
rotated by ~90° with respect to the similar loop in IX/X-bp.
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Figure 7.
Figure 7. Geometry around the Ca^2+-binding site in CLPs.
(A) Subunit A. (B) Subunit B. Superposition of the Ca^2+ ion
coordination site in IX/X-bp (green) with the corresponding site
in rhodocetin (blue). Glu 128A and Glu 120B of IX/X-bp are
replaced by Lys 128 in the -subunit and
Lys 124 in the  -subunit,
respectively. This substitution could prevent the metal ion from
binding rhodocetin.
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The above figures are
reprinted
by permission from the Protein Society:
Protein Sci
(2005,
14,
169-175)
copyright 2005.
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