1bf0
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(New page: 200px<br /><applet load="1bf0" size="450" color="white" frame="true" align="right" spinBox="true" caption="1bf0" /> '''CALCICLUDINE (CAC) FROM GREEN MAMBA DENDROAS...)
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Revision as of 09:28, 20 November 2007
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CALCICLUDINE (CAC) FROM GREEN MAMBA DENDROASPIS ANGUSTICEPS, NMR, 15 STRUCTURES
Overview
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.
About this Structure
1BF0 is a Single protein structure of sequence from Dendroaspis angusticeps. Full crystallographic information is available from OCA.
Reference
Conformational and functional variability supported by the BPTI fold: solution structure of the Ca2+ channel blocker calcicludine., Gilquin B, Lecoq A, Desne F, Guenneugues M, Zinn-Justin S, Menez A, Proteins. 1999 Mar 1;34(4):520-32. PMID:10081964
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