Exchange of conduction pathways between two related K+ channels.
The structure of the ion conduction pathway or pore of voltage-gated ion channels is unknown, although the linker between the membrane spanning segments S5 and S6 has been suggested to form part of the pore in potassium channels. To test whether this region controls potassium channel conduction, a 21-amino acid segment of the S5-S6 linker was transplanted from the voltage-activated potassium channel NGK2 to another potassium channel DRK1, which has very different pore properties. In the resulting chimeric channel, the single channel conductance and blockade by external and internal tetraethylammonium (TEA) ion were characteristic of the donor NGK2 channel. Thus, this 21-amino acid segment controls the essential biophysical properties of the pore and may form the conduction pathway of these potassium channels.
Hartmann
H A
HA
Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030.
Kirsch
G E
GE
Drewe
J A
JA
Taglialatela
M
M
Joho
R H
RH
Brown
A M
AM
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000502:physiology; D002678:Chimera; D003001:Cloning, Molecular; D005260:Female; D015640:Ion Channel Gating; D008564:Membrane Potentials; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D009865:Oocytes / Q000502:physiology; D016133:Polymerase Chain Reaction; D015221:Potassium Channels / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D051381:Rats; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D014981:Xenopus
D015345:Oligonucleotide Probes; D015221:Potassium Channels; D013757:Tetraethylammonium Compounds; D019789:Tetraethylammonium