The charybdotoxin family of K+ channel-blocking peptides
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چکیده
منابع مشابه
The charybdotoxin family of K+ channel-blocking peptides
For many years, neuronal K’ channels were pharmacological orphans, essential membrane proteins against which’ no natural toxins were known. While biochemically and physiologically useful high affinity ligands had been identified for Na’, Ca2+, and many ligand-gated channels, the best blocker available for K+ channels was tetraethylammonium. In 1982, this situation changed with the discovery by ...
متن کاملThe electronic structure and dipole moment of charybdotoxin, a scorpion venom peptide with K+ channel blocking activity
The electronic structure of charybdotoxin (ChTX), a scorpion venom peptide that is known to act as a potassium channel blocker, is investigated with the aid of quantum mechanical calculations. The dipole moment vector (=145 D) of ChTX can be stirred by the full length KcsA potassium channel’s macrodipole (=403 D) thereby assuming the proper orientation before binding the ion channel on the ce...
متن کاملMechanism of charybdotoxin block of the high-conductance, Ca2+- activated K+ channel
The mechanism of charybdotoxin (CTX) block of single Ca2+-activated K+ channels from rat muscle was studied in planar lipid bilayers. CTX blocks the channel from the external solution, and K+ in the internal solution specifically relieves toxin block. The effect of K+ is due solely to an enhancement of the CTX dissociation rate. As internal K+ is raised, the CTX dissociation rate increases in a...
متن کاملCharybdotoxin block of single Ca2+-activated K+ channels. Effects of channel gating, voltage, and ionic strength
Charybdotoxin (CTX), a small, basic protein from scorpion venom, strongly inhibits the conduction of K ions through high-conductance, Ca2+-activated K+ channels. The interaction of CTX with Ca2+-activated K+ channels from rat skeletal muscle plasma membranes was studied by inserting single channels into uncharged planar phospholipid bilayers. CTX blocks K+ conduction by binding to the external ...
متن کاملUnlocking Family Secrets K+ Channel Transmembrane Domains
a cloud of cations, effectively concentrating them above the level of surrounding anions. When the channel opens, hydrated cations rapidly accelerate by electrodif-and Children's Hospital fusion into an 18 A ˚ –long hydrophobic canal that leads into a wider, 10 A ˚ –long cavity. In this cavity, dozens of Boston, Massachusetts 02115 H 2 O molecules are attracted to the K ϩ ion to help shield its...
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ژورنال
عنوان ژورنال: Neuron
سال: 1995
ISSN: 0896-6273
DOI: 10.1016/0896-6273(95)90057-8