Potassium transport in a halophilic member of the bacteria domain: identification and characterization of the K+ uptake systems TrkH and TrkI from Halomonas elongata DSM 2581T.

ABSTRACT: The halophilic bacterium Halomonas elongata accumulates K+, glutamate, and the compatible solute ectoine as osmoprotectants. By functional complementation of Escherichia coli mutants defective in K+ uptake, we cloned three genes that are required for K+ uptake in H. elongata. Two adjacent genes, named trkA (1,374 bp) and trkH (1,449 bp), were identified on an 8.5-kb DNA fragment, while a third gene, called trkI (1,479 bp), located at a different site in the H. elongata chromosome, was found on a second 8.5-kb fragment. The potential protein expressed by trkA is similar to the cytoplasmic NAD+/NADH binding protein TrkA from E. coli, which is required for the activity of the Trk K+ uptake system. The deduced amino acid sequences of trkH and trkI showed significant identity to the transmembra

SUBMITTER: Kraegeloh A 

PROVIDER: S-EPMC545715 | biostudies-literature | 2005 Feb

REPOSITORIES: biostudies-literature