MjK1, a K+ channel from M. jannaschii, mediates K+ uptake and K+ sensitivity in E. coli.
The methanogenic and hyperthermophilic deep-sea archaeon Methanococcus jannaschii has three putative K+ channels, MVP (Mj0139), MjK1 (Mj0138.1) and MjK2 (Mj1357). The physiological function of these K+ channels was examined in a viability assay, using the Escherichia coli mutant LB2003 (kup1, DeltakdpABC5, DeltatrkA). While MjK2 expression had no effects on the potassium-dependent phenotype of LB2003, MVP and MjK1 complemented the deficiency at a concentration of 1 mM KCl. In contrast to KcsA, MthK and MVP, MjK1 strongly affected host cell viability at 10 and 100 mM KCl. The toxic effects were less pronounced when growth media were supplemented with the K+ channel blocker BaCl2.
Hellmer
Jens
J
Universität Hannover, Institut für Biophysik, Herrenhäuserstr. 2, D-30419, Hannover, Germany.
Zeilinger
Carsten
C
D000595:Amino Acid Sequence; D001483:Base Sequence; D002462:Cell Membrane / Q000502:physiology; D003001:Cloning, Molecular; D017931:DNA Primers; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology; D007700:Kinetics; D017017:Methanococcus / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D011188:Potassium / Q000378:metabolism*; D015221:Potassium Channels / Q000737:chemistry / Q000502:physiology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D015221:Potassium Channels; D011994:Recombinant Proteins; D011188:Potassium