Structural highlights
FunctionCTX5A_MESEU Toxin with unknown function in healthy organisms. On glioma cells, interacts with chloride channels (probably ClC-3/CLCN3) and MMP2 at the surface of glioma cells. This complex is then internalized via caveolae, thus inhibiting the chloride channels necessary for cell shrinkage and tumor propagation (By similarity). Publication Abstract from PubMedThe solution structure of insectotoxin 15A (35 residues) from scorpion Buthus eupeus was determined on the basis of 386 interproton distance restraints 12 hydrogen-bonding restraints and 113 dihedral angle restraints derived from 1H NMR experiments. A group of 20 structures was calculated with the distance geometry program DIANA followed by the restrained energy minimization with the program CHARMM. The atomic RMS distribution about the mean coordinate position is 0.64 +/- 0.11 A for the backbone atoms and 1.35 +/- 0.20 A for all atoms. The structure contains an alpha-helix (residues 10-20) and a three-stranded antiparallel beta-sheet (residues 2-5, 24-28 and 29-33). A pairing of the eight cysteine residues of insectotoxin 15A was established basing on NMR data. Three disulfide bridges (residues 2-19, 16-31 and 20-33) connect the alpha-helix with the beta-sheet, and the fourth one (5-26) joins beta-strands together. The spatial fold of secondary structure elements (the alpha-helix and the beta-sheet) of the insectotoxin 15A is very similar to those of the other short and long scorpion toxins in spite of a low (about 20%) sequence homology. [Determination of the spatial structure of insectotoxin 15A from Buthus erpeus by (1)H-NMR spectroscopy data],Lomize AL, Maiorov VN, Arsen'ev AS Bioorg Khim. 1991 Dec;17(12):1613-32. PMID:1815511[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References | ||||||||||||||||||||
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