Functional reconstitution of a prokaryotic K+ channel.
SliK, a K+ channel encoded by the Streptomyces KcsA gene, was expressed, purified, and reconstituted in liposomes. A concentrative 86Rb+ flux assay was used to assess the ion transport properties of SliK. SliK-mediated ionic flux shows strong selectivity for K+ over Na+ and is inhibited by micromolar concentrations of Ba2+, mirroring the basic permeation characteristic of eukaryotic K+ channels studied by electrophysiological methods. 86Rb+ uptake kinetics and equilibrium measurements also demonstrate that the purified protein is fully active.
Heginbotham
L
L
Department of Biochemistry, Howard Hughes Medical Institute, Brandeis University, Waltham, Massachusetts 02254, USA.
Kolmakova-Partensky
L
L
Miller
C
C
D000465:Algorithms; D001464:Barium / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D007700:Kinetics; D050356:Lipid Metabolism; D008081:Liposomes; D011188:Potassium / Q000378:metabolism; D015221:Potassium Channels / Q000737:chemistry / Q000302:isolation & purification / Q000502:physiology*; D011387:Prokaryotic Cells / Q000378:metabolism*; D012414:Rubidium Radioisotopes; D013302:Streptomyces / Q000378:metabolism
D008081:Liposomes; D015221:Potassium Channels; D012414:Rubidium Radioisotopes; D001464:Barium; D011188:Potassium