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Purification and reconstitution of potassium channel proteins from squid axon membranes
Author(s) -
Prestipino G.,
Valdivia H.H.,
Liévano A.,
Darszon A.,
Ramírez A.N.,
Possani L.D.
Publication year - 1989
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 - 10.1016/0014-5793(89)80798-7
Subject(s) - squid , squid giant axon , biophysics , potassium channel , axon , sodium channel , bursting , repolarization , membrane , voltage gated potassium channel , membrane potential , ion channel , chemistry , potassium , channel blocker , voltage gated ion channel , electrophysiology , biochemistry , biology , sodium , microbiology and biotechnology , neuroscience , receptor , ecology , organic chemistry , calcium
Voltage‐dependent K + channels are responsible for repolarization of the cell membrane during the late phase of the action potential. Here we report the purification of proteins from squid axon membranes which bind the K + ‐channel blocker noxiustoxin (NTX), and their subsequent functional reconstitution in planar bilayers. The NXT‐affinity purified proteins had M r values of 60000 ± 6000, 160000 ± 15000 and 220000 ± 20000. Their incorporation into bilayers resulted in single‐channel currents with three conductances, the most frequent one of 11 pS in 300/100 mM KCl ( cis / trans ). The voltage dependence, reversal potential and bursting behavior suggest that these are the K + channels involved in the squid axon action potential.