Three-dimensional structure of natural charybdotoxin in aqueous solution by 1H-NMR. Charybdotoxin possesses a structural motif found in other scorpion toxins
| Autor: | Flavio Toma, Christian Roumestand, François Bontems, André Ménez, Yvon Doljansky, Philippe Boyot, Bernard Gilquin |
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| Rok vydání: | 1991 |
| Předmět: |
Magnetic Resonance Spectroscopy
Charybdotoxin Stereochemistry Protein Conformation Molecular Sequence Data Kaliotoxin Scorpion Venoms Nuclear magnetic resonance spectroscopy Antiparallel (biochemistry) Biochemistry Protein tertiary structure chemistry.chemical_compound Protein structure chemistry Proton NMR Amino Acid Sequence Structural motif |
| Zdroj: | European journal of biochemistry. 196(1) |
| ISSN: | 0014-2956 |
| Popis: | A 600-MHz proton NMR study of natural charybdotoxin, a toxin acting on K+ channels, is reported. The unambiguous sequential assignment of all the protons of the toxin was achieved. The analysis of NOEs and of backbone coupling constants showed the existence of an alpha-helix (residues 10-19) and of an antiparallel beta-sheet in the 26-35 part. Three-dimensional structures were generated by distance geometry, using a set of 114 interresidual calibrated constraints (63 sequential, 47 medium and long range, 4 hydrogen bonds) and 29 phi angles. These structures show that charybdotoxin is composed of a beta-sheet linked to an alpha-helix by two disulphide bridges and to an extended fragment by the third disulphide bridge. Comparison with the other known structures of long and short scorpion toxins shows that this structural motif is common to all these proteins. |
| Databáze: | OpenAIRE |
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