Discrepin, a new peptide of the sub-family alpha-ktx15, isolated from the scorpion Tityus discrepans irreversibly blocks K+ -channels (IA currents) of cerebellum granular cells.
A new peptide was purified from the venom of the Venezuelan scorpion Tityus discrepans, by high-performance liquid chromatography and its amino acid sequence was completed by Edman degradation and mass spectrometry analysis. It contains 38 amino acid residues with a molecular weight of 4177.7 atomic mass units, tightly folded by three disulfide bridges, and has a pyroglutamic acid at the N-terminal region. This peptide, named Discrepin, was shown to block preferentially the IA currents of the voltage-dependent K+ -channel of rat cerebellum granular cells in culture. The K+ -currents are inhibited in an apparently irreversible manner, whose 50% inhibitory effect is reached with a 190 nM toxin concentration. The systematic nomenclature proposed for this toxin is alpha-KTx15.6.
D'Suze
Gina
G
Laboratory of Cellular Neuropharmacology, Biochemistry and Biophysics Center, Instituto Venezolano de Investigaciones Cientificas, Apartado 21827, Caracas 1020-A, Venezuela.
Batista
Cesar V F
CV
Frau
Andrea
A
Murgia
Anna Rosa
AR
Zamudio
Fernando Z
FZ
Sevcik
Carlos
C
Possani
Lourival D
LD
Prestipino
Gianfranco
G
D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects*; D004220:Disulfides; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009498:Neurotoxins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D012604:Scorpion Venoms / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology; D012605:Scorpions / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D012995:Solubility
D004220:Disulfides; D009498:Neurotoxins; D010455:Peptides; D015221:Potassium Channels; D012604:Scorpion Venoms; C492486:discrepin peptide, rat; C509989:discrepin protein, Tityus discrepans