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PDBsum entry 1bf0
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Calcium channel blocker
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PDB id
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1bf0
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References listed in PDB file
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Key reference
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Title
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Conformational and functional variability supported by the bpti fold: solution structure of the ca2+ channel blocker calcicludine.
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Authors
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B.Gilquin,
A.Lecoq,
F.Desné,
M.Guenneugues,
S.Zinn-Justin,
A.Ménez.
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Ref.
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Proteins, 1999,
34,
520-532.
[DOI no: ]
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PubMed id
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Note In the PDB file this reference is
annotated as "TO BE PUBLISHED".
The citation details given above were identified by an automated
search of PubMed on title and author
names, giving a
percentage match of
0%.
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Abstract
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Calcicludine, a 60-amino acid protein isolated from the green mamba venom, has
been recently identified as blocking a large set (i.e., L-, N- and P-type) of
Ca2+ channels. The three-dimensional structure of calcicludine has been
determined by NMR and molecular modeling using a data set of 723 unambiguous and
265 ambiguous distance restraints, as 33 phi and 13 chi1 dihedral angle
restraints. Analysis of the 15 final structures (backbone root-mean-square
deviation = 0.6 A) shows that calcicludine adopts the Kunitz-type protease
inhibitor fold. Its three-dimensional structure is similar to that of snake K+
channel blockers dendrotoxins. Conformational differences with protease
inhibitors and dendrotoxins are localized in the 3(10) helix and loop 1
(segments 1-7 and 10-19), the extremity of the beta-hairpin (segment 27-30), and
loop 2 (segment 39-44). These regions correspond to the functional sites of
bovine pancreatic trypsin inhibitor (BPTI) and dendrotoxins. The positioning of
the N-terminal segment 1-7 relative to the rest of the protein is characteristic
of calcicludine. The involvement of this segment and the positively charged K31
at the tip of the beta-hairpin in the biological activity of calcicludine is
discussed.
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Figure 1.
Figure 1. Sequence of calcicludine (cac) aligned with
dendrotoxin K (dtk),  -dendrotoxin
(dtx), dendrotoxin I (dem), BPTI, amyloid  -protein
precursor inhibitor (APPI), and ShPI isolated from the Caribbean
sea anemone Stichodactyla helianthus. Conserved residues are
indicated on the last line (@ : only the hydrophobic character
is conserved).
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Figure 6.
Figure 6. C -C
distances
between calcicludine solution structure and eight analogous
protein structures: dendrotoxin K (cyan line), -dendrotoxin
(purple line), ShPI (yellow line), APPI (black line), BPTI
(4pti, 1bpi and 1pit in solid, dashed and dash-dotted red line
respectively). to Protein Data Bank[57] entries are indicated in
Materials and Methods.
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The above figures are
reprinted
by permission from John Wiley & Sons, Inc.:
Proteins
(1999,
34,
520-532)
copyright 1999.
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