The identification of 114 integral membrane proteins from Halobacterium salinarum was achieved using liquid chromatography/tandem mass spectrometric (LC/MS/MS) techniques, representing 20% of the predicted alpha-helical transmembrane proteins of the genome. For this experiment, a membrane preparation with only minor contamination by soluble proteins was prepared. From this membrane preparation ...

Protein phosphorylation plays an important role in the two-component system based signal transduction pathways in bacteria and in archaea. These cascades have been identified also in the extremely halophilic archaeon Halobacterium salinarum and are well understood. Beside these protein phosphorylation events in which phosphorylation of histidine and aspartate residues are crucial, only little i...

Photoactivation of attractant phototaxis receptor sensory rhodopsin I (SRI) in Halobacterium salinarum entails transfer of a proton from the retinylidene chromophore's Schiff base (SB) to an unidentified acceptor residue on the cytoplasmic half-channel, in sharp contrast to other microbial rhodopsins, including the closely related repellent phototaxis receptor SRII and the outward proton pump b...

Exposure of Halobacterium halobium to 50 degrees C for 2.5 h in an aerobic environment resulted in a greater than twofold increase in the activity of the manganese-containing superoxide dismutase. Nondenaturing polyacrylamide gels stained for enzymatic activity did not reveal any additional isozymes of superoxide dismutase induced by the heat shock. The maximal effect was observed at 50 degrees...

The archaebacterium Halobacterium cutirubrum contains a single detectable, Mn-containing superoxide dismutase, which is encoded by the sod gene (B. P. May and P. P. Dennis, J. Biol. Chem. 264:12253-12258, 1989). The genome of H. cutirubrum also contains a closely related sod-like gene (slg) of unknown function that has a pattern of expression different from that of sod. The four amino acid resi...

Although the structure of the catalytic RNA component of ribonuclease P has been well characterized in Bacteria, it has been little studied in other organisms, such as the Archaea. We have determined the sequences encoding RNase P RNA in eight euryarchaeal species: Halococcus morrhuae, Natronobacterium gregoryi, Halobacterium cutirubrum, Halobacteriurn trapanicum, Methanobacterium thermoautotro...

Haloarchaea are adapted to high-salt environments and accumulate equally high salt concentrations in the cytoplasm. The genomes of representatives of six haloarchaeal genera have been fully or partially sequenced, allowing the analysis of haloarchaeal properties in silico. Transcriptome and proteome analyses have been established for Halobacterium salinarum and Haloferax volcanii. Genetic syste...

1. DNA-dependent RNA polymerase was purified 150-fold from crude extracts of the extreme halophile Halobacterium cutirubrum. 2. The enzyme requires the presence of native DNA and all four nucleoside triphosphates to incorporate '4C-labelled nucleoside triphosphate into an acid-insoluble ribonuclease-sensitive product. 3. It has an absolute requirement for both Mn2+ and Mg2+. 4. The polymerase r...