MjK1, a K + channel from M. jannaschii, mediates K + uptake and K + sensitivity in E. coli

• Published in: FEBS letters 2003-07, Vol.547 (1), p.165-169
• Main Authors: Hellmer, Jens, Zeilinger, Carsten
• Format: Article
• Language: English
• Subjects: Affinity purification; Amino Acid Sequence; Archaebacterial potassium channel; Base Sequence; Cell Membrane - physiology; Cloning, Molecular; Complementation; DNA Primers; Escherichia coli - genetics; Escherichia coli - physiology; KcsA, K+ channel A Streptomyces lividans; Kinetics; Methanococcus - genetics; Methanococcus - physiology; MjK1 and MjK2, Methanococcus jannaschii K+ channels 1 and 2; Molecular Sequence Data; MthK, Methanobacterium thermoautotrophicum K+ channel; MVP, methanococcal voltage-gated potassium channel; Potassium - metabolism; Potassium Channels - chemistry; Potassium Channels - physiology; RCK, regulators of K+ conductance; Recombinant Proteins - chemistry; Recombinant Proteins - metabolism; Sequence Alignment; Sequence Homology, Amino Acid; TrkA-N and TrkA-C, domains of potassium uptake systems
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(03)00706-3

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, ΔkdpABC5, ΔtrkA). 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 BaCl 2.