1BF0

CALCICLUDINE (CAC) FROM GREEN MAMBA DENDROASPIS ANGUSTICEPS, NMR, 15 STRUCTURES

Summary for 1BF0

• Entry DOI: 10.2210/pdb1bf0/pdb
• Descriptor: CALCICLUDINE (1 entity in total)
• Functional Keywords: calcium channel blocker
• Biological source: Dendroaspis angusticeps (eastern green mamba)
• Cellular location: Secreted: P81658
• Total number of polymer chains: 1
• Total formula weight: 6998.27

Authors

Gilquin, B.,Lecoq, A.,Desne, F.,Guenneugues, M.,Zinn-Justin, S.,Menez, A. (deposition date: 1998-05-26, release date: 1999-01-13, Last modification date: 2024-10-09)

Primary citation

Gilquin, B.,Lecoq, A.,Desne, F.,Guenneugues, M.,Zinn-Justin, S.,Menez, A.
Conformational and functional variability supported by the BPTI fold: solution structure of the Ca2+ channel blocker calcicludine.
Proteins, 34:520-532, 1999

PubMed Abstract: 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.

PubMed: 10081964
DOI: 10.1002/(SICI)1097-0134(19990301)34:4<520::AID-PROT11>3.3.CO;2-E

Experimental method

SOLUTION NMR