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Slotoxin, αKTx1.11, a new scorpion peptide blocker of MaxiK channels that differentiates between α and α+β (β1 or β4) complexes
Author(s) -
Garcia-Valdes Jesus,
Zamudio Fernando Z,
Toro Ligia,
Possan Lourival D
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)02791-0
Subject(s) - charybdotoxin , iberiotoxin , scorpion , peptide , chemistry , potassium channel , scorpion toxin , channel blocker , potassium channel blocker , stereochemistry , venom , biophysics , biochemistry , biology , organic chemistry , calcium
A novel peptide from Centruroides noxius Hoffmann scorpion venom was isolated and sequenced. The 37 amino acid peptide belongs to the charybdotoxin sub‐family (αKTx1) and was numbered member 11. αKTx1.11 has 75% sequence identity with iberiotoxin and 54% with charybdotoxin. αKTx1.11 revealed specificity for mammalian MaxiK channels (hSlo), thus, was named slotoxin. Slotoxin blocks the MaxiK pore‐forming α subunit reversibly ( K d =1.5 nM). Slotoxin association with α+β (β1 or β4) channels was ∼10 times slower than iberiotoxin and charybdotoxin, leading to a lack of effect on α+β4 when tested at 100 nM for 5 min. Thus, slotoxin is a better tool to distinguish MaxiK α+β complexes.